@conference {20_EUCAP2020_LENTE_BOULDER_EDUARDO, title = {Ka-band Multi-beam Planar Lens Antenna for 5G Applications}, booktitle = {2020 14th European Conference on Antennas and Propagation (EuCAP)}, year = {2020}, month = {March}, pages = {1-5}, abstract = {A low-cost solution for multi-beam antenna systems is explored for 5G applications in the 26-GHz band. A 4-port stacked-patch microstrip antenna is used as feeder of a perforated flat lens. Each feeder is placed in a different position with respect to the lens, yielding four high-directivity independent beams. The beams cover an angular range from broadside to a 30-degree steering with a gain over 18 dB. The antenna has been implemented by low-cost processes, employing Printed Circuit Board fabrication for the feeder and 3D printing for the lens.}, keywords = {5G mobile communication, Beam steering, Microstrip antennas}, doi = {10.23919/EuCAP48036.2020.9135364}, author = {E Garcia-Marin and D S Filipovic and J L Masa-Campos and P Sanchez-Olivares} } @article {20_LENTE_PARCHES_BOULDER_EDUARDO, title = {Low-cost lens antenna for 5G multi-beam communication}, journal = {Microwave and Optical Technology Letters}, volume = {n/a}, number = {n/a}, year = {2020}, abstract = {Abstract A planar dielectric lens has been designed for low-cost multi-beam antennas in the 26-GHz band of 5G communications. The lens feeder is a stacked-patch microstrip antenna with four input ports, thus permitting four independent high-directivity radiation beams. Maximum steering of 25{\textdegree} can be attained, which a simulated gain over 18 dB for all scanning angles. The antenna has been implemented with low-cost manufacturing techniques. The feeder is fabricated as a printed circuit board, while the lens is realized as a perforated 3D-printed dielectric piece. Experimental results confirm the multi-beam capability of the lens system, suggesting that the spillover efficiency can be improved in further works.}, keywords = {5G mobile communication, Beam steering, Microstrip antennas}, doi = {10.1002/mop.32486}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mop.32486}, author = {E Garcia-Marin and D S Filipovic and J L Masa-Campos and P Sanchez-Olivares} } @article {18_AWPL_PABLO-SANCHEZ_CORPORATE-ARRAY-TUNING-SCREWS, title = {Mechanically Reconfigurable Linear Array Antenna Fed by a Tunable Corporate Waveguide Network With Tuning Screws}, journal = {IEEE Antennas and Wireless Propagation Letters}, volume = {17}, number = {8}, year = {2018}, month = {Aug}, pages = {1430-1434}, abstract = {A mechanical technique to provide beam-steering capabilities to a linear array antenna is presented. The methodology is based on the insertion of metallic tuning screws into power dividers in rectangular waveguide technology. These tuning screws establish a short circuit between the top and bottom plates of the waveguide, and a phase change in the transmitted signal is then generated. Therefore, the phase difference between the output ports of a conventional waveguide divider can be controlled with these tuning screws. A corporate waveguide feeding network with several tuning screws has been designed. This tunable waveguide network is used to feed an aperture stacked patch array, forming the final mechanically reconfigurable linear array. Seven different phase configurations have been synthetized by using the tuning screws, which provide a noncontinuous angular scanning. In particular, a main beam steering from -26{\textdegree} to +26{\textdegree} with 13 discrete radiation patterns has been obtained. The use of waveguide technology makes the proposed reconfigurable antenna suitable for low-loss and high-power applications. Total efficiency values higher than 90\% have been achieved for every configuration.}, keywords = {Aperture-coupled antennas, Beam steering, Electromagnetic waveguides, Fasteners, linear antenna arrays, microwave antenna arrays, Tuning, waveguide arrays}, issn = {1536-1225}, doi = {10.1109/LAWP.2018.2848911}, url = {https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=8388289}, author = {P Sanchez-Olivares and J L Masa-Campos and A T Muriel-Barrado and R Villena-Medina and G M Fernandez-Romero} } @conference {14_EuMC_Ruiz-CruzFahmiMansour_Single-PoleMultiple-ThrowWaveguide, title = {Single-Pole Multiple-Throw Waveguide Switch for Twelve Output Ports}, booktitle = {Proc. 44th European Microwave Conference}, year = {2014}, issn = {978-1-61284-235-6}, author = {J A Ruiz-Cruz and Fahmi, M M and Mansour, R R} } @conference {13_IMS_Ruiz-CruzFahmiMansour_Single-PoleSix-ThrowWaveguideSwitch, title = {Single-Pole Six-Throw Waveguide Switch Embedded in a Seven Port Loaded Junction}, booktitle = {2013 IEEE MTT-S International Microwave Symposium Digest}, year = {2013}, month = {Nov}, pages = {1-4}, abstract = {A waveguide switch with six states involving seven ports is presented in this paper. It consists of a common port that feeds perpendicularly six output routing branches placed in the same plane. The switch is based on actuating short circuit loads in six ridge waveguide branches. It avoids the use of complex rotary systems to provide path switching, resulting in an extremely compact profile and simplifying the manufacturing. The concept is presented based on rigorous full-wave simulations and experimental results of a Ku-band SP6T, which is designed, built and tested. The experimental proof of this new switch integrates the transitions to SMA outputs and the short-circuit loads. It shows measured return loss better than 25 dB in a 12\% fractional bandwidth in the best state and 20 dB in an 8\% bandwidth in the worst state. The isolation of this prototype is at least 32 dB, with insertion loss of 0.3-0.4 dB.}, author = {J A Ruiz-Cruz and Fahmi, M M and Mansour, R R} } @conference {12_IMS_Ruiz-CruzFahmiMansour_Dual-ResonanceComblineResonator, title = {Dual-Resonance Combline Resonator for Dual-Band Filters}, booktitle = {2009 IEEE MTT-S International Microwave Symposium Digest}, year = {2012}, month = {June}, pages = {1-3}, abstract = {A novel combline resonator is introduced in this paper for realizing compact microwave dual-band filters. The basic resonator is based on the well-known combline topology, where an additional metallic conductor is introduced for having two TEM modes. The resonant frequencies of the two asynchronous TEM resonant modes are controlled by the length of the two concentric conductors and their spacing. The proposed structure is employed to realize a dual-band filter, where each combline resonator provides one resonant mode per pass-band. The control of the filter parameters, such as pass-band bandwidths and band separation, is addressed. These filters harness the advantages of combline technology for dual-band filters, using the compactness provided by the proposed resonator. A complete design is introduced. Simulations as well as experimental results are presented showing excellent agreement, thus validating the proposed concept.}, issn = {0149-645X}, doi = {10.1109/MWSYM.2012.6259436}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6259436}, author = {J A Ruiz-Cruz and Fahmi, M M and Mansour, R R} } @conference {12_IMS_DaneshmandA.FahmiEtAl_MEMSMultiportSwitches, title = {MEMS Multiport Switches and Switch Matrices for Satellite Applications}, booktitle = {2012 IEEE MTT-S International Microwave Symposium Digest}, year = {2012}, month = {June}, pages = {1-4}, issn = {0149-645X}, author = {Daneshmand, M and Fomani, A A and Fahmi, M M and J A Ruiz-Cruz and Mansour, R R} } @article {19_Propagation5.6GHzPIER-C, title = {Propagation Loss Measurement due to Miscellaneous Phenomenon at 5.6 GHz Band}, journal = {PIER-C: Progress in Electromagnetics Research C}, volume = {32}, year = {2012}, month = {Oct.}, pages = {207-220}, abstract = {In this work, the propagation loss due to diffraction and insertion losses for indoor scenario at 5.6 GHz band are measured using directive antenna and a Vector Network Analyzer (VNA). It is shown that the insertion loss of a metallic door with porthole window varies from several dB due to the propagation loss via the porthole glass up to 50 dB due to the diffraction by the porthole boards when the line between the transmitting antenna and receiving one is outside the porthole glass. It is shown that the insertion loss of a 12 cm brick wall is 4.8 dB for vertical polarization while it is 6.3 dB for horizontal polarization. Also it is shown the diffraction loss due single or double concrete columns depends on the distance between the transmitting and receiving antennas.}, issn = {1937-8718}, doi = {10.2528/PIERC12072304}, url = {http://www.jpier.org/PIERC/pierc32/16.12072304.pdf}, author = {B Taha-Ahmed and J L Masa-Campos and F Fern{\'a}ndez-Campillo} } @article {18_Propagation5.5GHzPIER, title = {Short Range Propagation Model For a Very Wideband Directive Channel at 5.5 GHz Band}, journal = {PIER - Progress in Electromagnetics Research}, volume = {130}, year = {2012}, month = {Sep.}, pages = {319-346}, abstract = {In this work, the propagation loss of three short range directive channels at 5.5 GHz is measured using different directive antennas and a Vector Network Analyzer (VNA). Results are given for a channel bandwidth of 300 MHz which will be the future channel bandwidth of IEEE 802.11 ac system. It has been noted that the multipath induced fading tends to have Normal Distribution at low distance between the transmitting and the reception antennas. At higher distances, it tends to have Normal distribution plus Rayleigh one. Channel Impulse response (CIR) is also measured indicating that the main contribution is due to the direct ray and the one reflected from the floor. The human being obstruction causes an extra propagation loss of 2 to 10 dB depending on its distance from the transmitting antenna.}, issn = {1559-8985}, doi = {10.2528/PIER12060509}, url = {http://www.jpier.org/PIER/pier130/16.12060509.pdf}, author = {B Taha-Ahmed and F Fern{\'a}ndez-Campillo and J L Masa-Campos} } @article {12_IEEETMTT_Ruiz-CruzFahmiMansour_Triple-ConductorComblineResonators, title = {Triple-Conductor Combline Resonators for Dual-Band Filters With Enhanced Guard-Band Selectivity}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {60}, number = {12}, year = {2012}, month = {December}, pages = {3969-3979}, abstract = {Novel combline resonators and filters with enhanced dual-band characteristics are introduced in this paper. The proposed resonator is made up of three metallic conductors: an inner post, an intermediate conductor, and an enclosure. This structure provides two asynchronous resonant modes that can be used for realizing compact microwave dual-band filters. Such dual-band filters offer the low cost, compact size, and ease of manufacturing features of traditional combline resonator filters, with additional size reduction due to the fact that a single physical cavity provides two electrical resonators. In addition, the new cavity introduces a transmission zero in the guard-bands enhancing the filter selectivity, while keeping a simple and compact inline topology. The design of filters based on this novel resonator is discussed, starting with the resonator circuit model, the coupling scheme, and the complete filter design methodology. Simulations as well as experimental results of a tenth-order $(2 times 5)$ dual-band filter with a measured rejection level in excess of 100 dB in the guard-band are presented to show the concept.}, keywords = {Dual-resonance TEM-mode filters, multiband filters, multiconductor combline, re-entrant cross section}, issn = {0018-9480}, doi = {10.1109/TMTT.2012.2223482}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6354010}, author = {J A Ruiz-Cruz and Fahmi, M M and Mansour, R R} } @conference {11_IMS_Ruiz-CruzFahmiMansour_Compactfour-portRectWgSwitches, title = {Compact four-port rectangular waveguide switches based on simple short circuit loads}, booktitle = {2011 IEEE MTT-S International Microwave Symposium Digest}, year = {2011}, month = {June}, pages = {1-4}, abstract = {Four-port rectangular waveguide switches presented in this paper are based on alternating simple short and open circuit loads in the waveguide path. The proposed concept eliminates the use of bulky rotary mechanisms to provide path switching. The device layout is very simple and compact and is presented for C-, R- and T-type switches. The experimental performance of a T-type switch shows a return loss better than 23 dB from 13 to 14.5 GHz, insertion loss of 0.3 $\#$x2013;0.4 dB and isolation of 28 dB.}, issn = {0149-645X}, doi = {10.1109/MWSYM.2011.5973154}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5973154}, author = {J A Ruiz-Cruz and Fahmi, M M and Mansour, R R} } @conference {11_IMS_Ruiz-CruzFahmiDaneshmandEtAl_CompactreconfigurableWgCircularPol, title = {Compact reconfigurable waveguide circular polarizer}, booktitle = {2011 IEEE MTT-S International Microwave Symposium Digest}, year = {2011}, month = {June}, pages = {1-4}, abstract = {A waveguide circular polarizer with reconfigurable polarization sense is proposed in this paper. The polarizer can be switched between right and left hand circular polarization. The polarization sense is controlled by RF MEMS switches, which commute between two states for allowing or blocking adequately two different signal paths inside the waveguide structure. The polarizer is made up of three building blocks, involving E-plane waveguide MEMS SP2T switch, ridge to waveguide transitions and a septum-orthomode transducer. A switchable Ku-band polarizer prototype is designed and tested as a proof of concept. The experimental performance shows acceptable return losses and axial ratio levels in the 12.7 to 14.8 GHz band (15.3\% fractional bandwidth). The proposed structure is compact and is useful for applications that require fast polarization switching.}, issn = {0149-645X}, doi = {10.1109/MWSYM.2011.5972872}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5972872}, author = {J A Ruiz-Cruz and Fahmi, M M and Daneshmand, M and Mansour, R. R} } @article {11_IEEETMTT_Ruiz-CruzFahmiMansour_GeneralizedMulti-PortWgSwicthesShortCktLoads, title = {Generalized Multi-Port Waveguide Switches Based on Multiple Short-Circuit Loads in Power Divider Junctions}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {59}, number = {12}, year = {2011}, month = {December}, pages = {3347 - 3355}, abstract = {This paper presents a new concept for multiport waveguide switches based on short-circuit loads integrated in power-divider ridge-waveguide junctions. The switching is achieved by means of actuating short and open circuit loads in the waveguide path of a ridge waveguide, eliminating the need of bulky rotors, which are typically used in conventional waveguide switches. A complete class of single-pole N -throw switches (N up to 4) is presented based on this concept. Furthermore, the concept is employed to demonstrate highly compact C-, R-, and T-type waveguide switches by integrating different power-divider junctions in a seamless manner. The T-type case involves three states that provide the maximum flexibility for realizing advanced switch matrices for signal routing. A T-type waveguide switch is built and measured for validating the concept. To our knowledge, this paper marks the first time R- and T-type waveguide switches are demonstrated without the need to use a bulky rotary junction}, keywords = {multi-port ridge waveguide divider, rectangular waveguide switch, redundancy switch matrix, short-circuit loaded ridge waveguide, SPNT, three-state switch}, issn = {0018-9480}, doi = {10.1109/TMTT.2011.2170089}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6069588}, author = {J A Ruiz-Cruz and Fahmi, M M and Mansour, R R} } @article {11_JoCN_FahmiRuiz-CruzMansourEtAl_RecentAdvancesinFiltersSatellite, title = {Recent Advances in Filter Topologies and Realizations for Satellite Communications}, journal = {Journal of Communications and Networks}, volume = {13}, number = {6}, year = {2011}, month = {Dec}, pages = {625-632}, abstract = {This paper presents an overview of recent advances in radio frequency and microwave filter topologies for satellite communication systems. Many types of filters have been developed during the last years in order to satisfy the demands of modern applications in both terrestrial systems and onboard spacecrafts, leading to a great variety of aspects such as transfer functions, resonator implementations or coupling structures. This paper revisits some of the last advances in this area, including the modeling and full-wave simulation. Some recent designs using dual-mode cavities along with other novel implementations in ridge waveguide will be shown.}, keywords = {full-wave simulators, RF and microwave filters, waveguide technologies}, issn = {1229-2370}, doi = {10.1109/JCN.2011.6157479}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6157479}, author = {Fahmi, M M and J A Ruiz-Cruz and Mansour, R R and Zaki, K A} } @article {11_IETMAP_FahmiRuiz-CruzMansourEtAl_RecentLTCC, title = {Recent Results on Compact Broad-Band and Multi-Band LTCC Components for RF Front-Ends}, journal = {IET Microwaves, Antennas and Propagation}, volume = {5}, number = {8}, year = {2011}, month = {June}, pages = {870-876}, abstract = {Compact components for radio frequency (RF) front-ends realised in low-temperature co-fired ceramics (LTCC) are presented. The aim of this study was to highlight recent advances in realisation of different components for modern RF/microwave subsystems, stressing such attributes as compactness, wide bandwidth and operation in multiple bands. Two key components of every RF front-end are filters and couplers. To illustrate the feasibility of using LTCC technology to realise these components, several designs of filters and couplers are presented. Very compact LTCC ridge waveguide filter covering the whole US ultra-wide band is first discussed, followed by a dual-band LTCC ridge waveguide filter. Two types of wide-band couplers are shown: ridge waveguide couplers realised in LTCC and empty metallic waveguide and also a strip-line LTCC coupler. A common characteristic that will be shown is that the presented components by the authors are modelled using computer-aided design tools based on modal analysis for waveguides as well as commercially available finite-element tools. The shown examples have simulation results compared by different methods as well as some experimental results in LTCC and empty metallic waveguide, used to demonstrate the proposed approach.}, issn = {1751-8725}, doi = {10.1049/iet-map.2010.0371}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5936984\&tag=1}, author = {Fahmi, M M and J A Ruiz-Cruz and Mansour, R R and Zaki, K A} } @article {11_IEEETMTT_Ruiz-CruzFahmiFouladiEtAl_WaveguideAntennaFeedersReconfDualCircPol, title = {Waveguide Antenna Feeders with Integrated Reconfigurable Dual Circular Polarization}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {59}, number = {12}, year = {2011}, month = {December}, pages = {3365 - 3374}, abstract = {Waveguide antenna feeders with reconfigurable circular polarization sense are proposed in this paper. They can be switched between right and left hand circular polarization, without any mechanical rotation between the feeder and the antenna. Two types of feeders are presented. The polarizer works with a single switchable polarization for each state. The dual feeder can work with both polarizations at the same frequency band simultaneously, each one associated with a different rectangular waveguide port. The polarization sense is controlled by metallic posts that block or open the signal paths connecting the rectangular ports with a septum-orthomode polarizer. These posts are automated with piezo-motors integrated in the structure, leading to a very compact layout, reduced size, and practical for applications with diverse switching speed. The proof of concept and the automation are shown with experimental Ku-band prototypes.}, keywords = {piezo-motor controlled feeder, polarization switch, Reconfigurable antenna feeder, waveguide septum OMT-polarizer}, issn = {0018-9480}, doi = {10.1109/TMTT.2011.2170581}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6068261}, author = {J A Ruiz-Cruz and Fahmi, M M and Fouladi, S and Mansour, R R} } @conference {10_IMS_FahmiRuiz-CruzMansourEtAl_CompactDualBandRidge, title = {Compact Wide-Band Ridge Waveguide Dual-Band Filters}, booktitle = {2010 IEEE MTT-S International Microwave Symposium Digest}, year = {2010}, month = {May}, pages = {888-891}, abstract = {A compact wide-band, dual-band filter realized in air filled metallic ridge waveguides is proposed. Dual-band filters replace doubly multiplexed filters, thus simplifying the system architecture considerably. The filter is realized in a canonical folded structure layout. Coupling sections that realize strong coupling values required for the wide-band characteristics are achieved by means of transversal sections of ridges connecting the main ridge waveguide resonators. The filter is efficiently modeled using rigorous mode matching method. The filter response is further verified using a commercially available Finite Element Method software. In addition a prototype was built and tested for verification.}, issn = {0149-645X}, doi = {10.1109/MWSYM.2010.5517525}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=05517629}, author = {Fahmi, M M and J A Ruiz-Cruz and Mansour, R R and Zaki, K A} } @conference {09_IMS_FahmiRuiz-CruzZakiEtAl_CompactRidgeNRN, title = {Compact Ridge Waveguide Filters using Non-resonating Nodes}, booktitle = {2009 IEEE MTT-S International Microwave Symposium Digest}, year = {2009}, month = {June}, pages = {1337-1340}, abstract = {A ridge waveguide filter based on the nonresonating node (NRN) concept is proposed. A new coupling mechanism, suitable for this realization is introduced. The proposed coupling mechanism alleviates the need to use other complicated structures and simplify the design process significantly. Rigorous mode matching method (MMM) is used to model the filter. The filter response is further verified using another numerical technique. A prototype was built and tested. Measurement results agree well with simulation.}, issn = {0149-645X}, doi = {0.1109/MWSYM.2009.5165952}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=5165952\&isnumber=5165586}, author = {Fahmi, M M and J A Ruiz-Cruz and Zaki, K A and Mansour, R R} } @article {09_IEEETMTT_FahmiRuiz-CruzMansourEtAl_CompactRidgeWaveguideTZNRN, title = {Compact Ridge Waveguide Filters With Arbitrarily Placed Transmission Zeros Using Nonresonating Nodes}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {57}, number = {12}, year = {2009}, month = {Dec.}, pages = {3354-3361}, abstract = {Compact size ridge waveguide filters based on the nonresonating node concept are introduced to realize transfer functions with arbitrarily placed attenuation poles. Coupling mechanisms, suitable for the new realization are introduced in diverse $E$ -plane and $H$ -plane configurations and with different input-output interfaces. These coupling structures are studied and characterized in detail in order to simplify the design of the proposed filters. Rigorous mode-matching method is used to accelerate the full-wave design of the filter configurations, whose response is also verified using other numerical techniques and experimental data. To validate the proposed novel designs, a prototype has been built and tested. Measurement results agree well with the predicted theoretical simulations.}, keywords = {Attenuation poles, microwave filters, mode-matching, ridge waveguides}, issn = {0018-9480}, doi = {10.1109/TMTT.2009.2034423}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=5308444\&isnumber=5340253}, author = {Fahmi, M M and J A Ruiz-Cruz and Mansour, R R and Zaki, K A} } @article {7_Stacked_Patch_X_bandMOTL, title = {Monopulse beam-scanning planar array antenna in L band}, journal = {Microwave and Optical Technology Letters}, volume = {51}, number = {6}, year = {2009}, month = {Jun.}, pages = {1419-1424}, abstract = {A planar antenna is presented as part of a Signal Identification System working at 1.06 GHz. The antenna presents a monopulse radiation pattern. Likewise, a scanning of the main beam direction is achieved in a {\textpm}45{\textdegree} azimuth coverage. A limited 3 dB amplitude drop of the received signal at the edges of the angular scanning area is only permitted. Furthermore, a broad beamwidth is required in the single element of the array. A rectangular linearly polarized double stacked patch has been then designed, with a significant size reduction in the nonresonant length, to increase the azimuth beamwidth of the array single element. The whole antenna structure is composed of 18 elements, which have been distributed in six columns of three patches per column. The feeding network of the array has been developed in microstrip technology, with small individual circuits connected by coaxial cables, to reduce the global losses of the system. The designed compact antenna and the transmitting and receiving equipments will be placed inside a POD on the top part of an airplane. A prototype antenna has been manufactured and measured in three different beam pointing directions. Satisfactory results have been achieved in the entire frequency band.}, keywords = {beam-scanning array, monopulse system, stacked patch}, issn = {0895-2477}, doi = {10.1002/mop.23516}, url = {http://onlinelibrary.wiley.com/doi/10.1002/mop.23516/abstract}, author = {J L Masa-Campos and S{\'a}nchez-Sevilleja, S and Dom{\'\i}nguez-Grano-de-Oro, C and Sierra-P{\'e}rez, M and Fernandez-Jambrina, J L} } @article {08_IJRFMiCAE_FahmiRuiz-CruzZaki_EandH-plane, title = {E and H-plane wide-band ridge waveguide couplers}, journal = {International Journal of RF and Microwave Computer-Aided Engineering}, volume = {18}, number = {4}, year = {2008}, month = {July}, pages = {348-358}, abstract = {A systematic synthesis procedure for ridge waveguide branch line couplers in both E-plane and H-plane configurations is presented. Ridge waveguides are chosen to benefit from their wide mono-mode band and compact size compared to rectangular waveguides. Equivalent circuit parameters are used to synthesize the coupler sections. Rigorous mode matching method is used for full-wave analysis and optimization of the couplers. Ridge couplers both in empty waveguide and Low Temperature Co-fired Ceramic "LTCC" technology are designed using the proposed method and the design is verified with another numerical method. A prototype is built and its response is measured to verify the approach}, keywords = {full-wave, LTCC, mode matching, optimization, ridge waveguide}, issn = {1096-4290}, doi = {10.1002/mmce.20293}, url = {http://www3.interscience.wiley.com/cgi-bin/fulltext/119140987/PDFSTART}, author = {Fahmi, M M and J A Ruiz-Cruz and Zaki, K A} } @article {6_Monopulse_L_BandMOTL, title = {Monopulse beam-scanning planar array antenna in L band}, journal = {Microwave and Optical Technology Letters}, volume = {50}, number = {7}, year = {2008}, month = {Jul.}, pages = {1812-1819}, abstract = {A planar antenna is presented as part of a Signal Identification System working at 1.06 GHz. The antenna presents a monopulse radiation pattern. Likewise, a scanning of the main beam direction is achieved in a {\textpm}45{\textdegree} azimuth coverage. A limited 3 dB amplitude drop of the received signal at the edges of the angular scanning area is only permitted. Furthermore, a broad beamwidth is required in the single element of the array. A rectangular linearly polarized double stacked patch has been then designed, with a significant size reduction in the nonresonant length, to increase the azimuth beamwidth of the array single element. The whole antenna structure is composed of 18 elements, which have been distributed in six columns of three patches per column. The feeding network of the array has been developed in microstrip technology, with small individual circuits connected by coaxial cables, to reduce the global losses of the system. The designed compact antenna and the transmitting and receiving equipments will be placed inside a POD on the top part of an airplane. A prototype antenna has been manufactured and measured in three different beam pointing directions. Satisfactory results have been achieved in the entire frequency band.}, keywords = {beam-scanning array, monopulse system, stacked patch}, issn = {0895-2477}, doi = {10.1002/mop.23516}, url = {http://onlinelibrary.wiley.com/doi/10.1002/mop.23516/abstract}, author = {J L Masa-Campos and S{\'a}nchez-Sevilleja, S and Dom{\'\i}nguez-Grano-de-Oro, C and Sierra-P{\'e}rez, M and Fernandez-Jambrina, J L} } @article {4_Omni_antenna_parasiticstripsMOTL, title = {Circularly polarized omnidirectional millimeter wave monopole with parasitic strip elements}, journal = {Microwave and Optical Technology Letters}, volume = {49}, number = {3}, year = {2007}, month = {Mar.}, pages = {664-668}, abstract = {A circularly polarized omnidirectional millimeter wave monopole with parasitic strip elements for a system of arrival signal direction detection in millimeter band is presented. As a consequence of the radiation pattern requirements, the proposed antenna consists of a conical skirt monopole with a polarizer radome. The polarizer converts a wave from linear to circular polarization. The proposed antenna has the advantage to be robust, low cost, and easy to fabricate with conventional materials and printed circuit technology. The study presents simulation and experimental results obtained with an antenna prototype that validate the design.}, keywords = {arrival signal direction detection system, Circular polarization, millimeter antenna, omnidirectional antenna}, issn = {0895-2477}, doi = {10.1002/mop.22237}, url = {http://onlinelibrary.wiley.com/doi/10.1002/mop.22237/abstract}, author = {Fern{\'a}ndez, J M and J L Masa-Campos and Sierra-P{\'e}rez, M} } @article {5_Omni_antenna_slotsMOTL, title = {Omnidirectional circularly polarized slot antenna fed by a cylindrical waveguide in millimeter band}, journal = {Microwave and Optical Technology Letters}, volume = {49}, number = {3}, year = {2007}, month = {Mar.}, pages = {638-642}, abstract = {A circularly polarized slotted array antenna is presented. The array is fed by a circular waveguide propagating the TM01, to properly generate the required polarization. An omnidirectional azimuth radiation pattern is obtained, as well as a ?10{\textdegree}/+30{\textdegree} elevation antenna coverage. Low losses are achieved because of the waveguide feed. The slot array is mechanized over the metallic wall of the circular waveguide. Furthermore, the antenna presents a solid and rigid mechanical structure, which guarantees an optimum and repetitive response in a manufacturing process. A prototype antenna has been designed and measured. Satisfactory results have been obtained. The slotted array takes part from a signal detection system centered in 36.85 GHz.}, keywords = {Circular polarization, conformal slotted waveguide array, transversal magnetic mode, waveguide to coaxial transition}, issn = {0895-2477}, doi = {10.1002/mop.22207}, url = {http://onlinelibrary.wiley.com/doi/10.1002/mop.22207/abstract}, author = {J L Masa-Campos and Fern{\'a}ndez, J M and Sierra-P{\'e}rez, M} } @conference {06_EuMC_Ruiz-CruzZhangFahmiEtAl_RidgeWaveguideElliptic, title = {Ridge Waveguide Elliptic Filters in Narrow-Wall Canonical Configuration}, booktitle = {Proc. 36th European Microwave Conference}, year = {2006}, month = {Sept.}, pages = {1080-1082}, abstract = {A new canonical ridge waveguide structure is proposed to design elliptic filter responses. The non-adjacent cavities are coupled by windows situated at the common narrow-wall of the ridge waveguide enclosures. This new configuration provides positive and negative cross couplings using evanescent rectangular waveguides and metallic strips, respectively. The full-wave analysis of the structure is carried out by a rigorous mode matching method. The design is based on circuit synthesis and full-wave optimization. Finally, the proposed structure is elucidated with the design of a four-pole filter and it is validated with the commercial HFSS software}, keywords = {circuit synthesis, elliptic filters, four-pole filter, full-wave optimization, metallic strips, mode matching, mode matching method, narrow-wall canonical configuration, negative cross couplings, network synthesis, nonadjacent cavities, positive cross couplings, rectangular waveguides, ridge waveguide elliptic filters, ridge waveguides, waveguide filtersHFSS software}, issn = {2-9600551-6-0}, doi = {10.1109/EUMC.2006.281121}, url = {http://ieeexplore.ieee.org/iel5/4057701/4057702/04058011.pdf?tp=\&isnumber=\&arnumber=4058011}, author = {J A Ruiz-Cruz and Zhang, Y and Fahmi, M M and Zaki, K A} } @article {3_CouplingJMOEA, title = {Coupling Characterization and Compensation Model for Antenna Arrays}, journal = {Journal of Microwaves, Optoelectronics and Electromagnetic Applications}, volume = {4}, number = {2}, year = {2005}, month = {Dec.}, pages = {95-110}, abstract = {Coupling is an important aspect to be considered in the design process of antenna arrays. The real feeding radiated coefficients can be quite different from the theoretical ones because of this effect. In this paper, a characterization and compensation model is presented. This procedure is capable of matching each element of the array. All the parameters of the array coupling model are obtained through the measurement of scattering parameters and radiation patterns of the individual elements. Some practical applications to linear patch arrays are presented.}, issn = {1516-7399}, url = {http://www.jmoe.org/site-number?id=3}, author = {J L Masa-Campos and Fern{\'a}ndez, J M and Sierra-Casta{\~n}er, M and Sierra-P{\'e}rez, M} } @conference {05_IMS_FahmiRuiz-CruzZakiEtAl_LTCCwide-bandcanonical, title = {LTCC wide-band canonical ridge waveguide filters}, booktitle = {2005 IEEE MTT-S International Microwave Symposium Digest}, year = {2005}, month = {June}, pages = {249-252}, abstract = {A canonical LTCC ridge waveguide filter for wide-band application is proposed. A new coupling scheme is employed to achieve the values of the cross couplings needed to increase the bandwidth. The change of the realization of the coupling sections from rectangular to narrow ridge waveguide is shown to eliminate detrimental undesired cross coupling. To validate the concept, rigorous mode matching method is used for full-wave analysis and optimization of a six pole filter. The response is verified with another numerical method, and a prototype is constructed for testing.}, keywords = {canonical ridge waveguide filters, ceramic packaging, coupling scheme, coupling sections, full-wave analysis, mode matching, mode matching method, narrow ridge waveguide, optimisation, ridge waveguides, six pole filter, waveguide filters LTCC, wide-band filters}, issn = {01490-645X}, doi = {10.1109/MWSYM.2005.1516572}, url = {http://ieeexplore.ieee.org/iel5/10171/32491/01516572.pdf?tp=\&isnumber=\&arnumber=1516572}, author = {Fahmi, M M and J A Ruiz-Cruz and Zaki, K A and Piloto, A J} } @article {1_CouplingmodelMOTL, title = {Estimation of the patch-array-coupling model through radiated-field measurements}, journal = {Microwave and Optical Technology Letters}, volume = {43}, number = {1}, year = {2004}, month = {Oct.}, pages = {59-65}, abstract = {In the design process of array antennas, coupling is one of the most important elements to be considered. The real feeding-radiated coefficients can be quite different from the theoretical ones because of this effect. In this paper, a characterization method is presented that allows each element to be matched from the array. All the parameters of the array-coupling model are obtained through the measurement of scattering parameters and radiation patterns. Two practical applications for a linear patch array are presented.}, keywords = {array, coupling, patch antenna, planar antenna}, issn = {0895-2477}, doi = {10.1002/mop.20375}, url = {http://onlinelibrary.wiley.com/doi/10.1002/mop.20375/abstract}, author = {Fern{\'a}ndez, J M and J L Masa-Campos and Sierra-Casta{\~n}er, M and Castellanos, D and Sierra-P{\'e}rez, M} }