@article {10_IEEEMWCL_ZhangRuiz-CruzZaki_WaveguideMicrostripTransition,
	title = {A Waveguide to Microstrip Inline Transition With Very Simple Modular Assembly},
	journal = {IEEE Microwave and Wireless Components Letters},
	volume = {20},
	number = {9},
	year = {2010},
	month = {Sept.},
	pages = {480-482},
	abstract = {A microstrip to empty rectangular waveguide transition is presented for systems requiring a simple modular assembly with good electrical performance. The structure is based on three building blocks, involving a microstrip line to dielectric-loaded rectangular waveguide, a transition between dielectric-loaded and empty rectangular waveguides with reduced height, and a final transformer to standard waveguide. These three building blocks (segmentation based on the design point of view) are combined in three simple parts which are assembled in a straightforward modular way, without soldering. These features are very important for signal feeders requiring a large number of transitions, as the X-band phased array antenna where the proposed structure has been integrated. The concepts involved in the design and manufacturing are illustrated with a prototype showing measured return loss of 10 dB and insertion loss of 1.1 dB in the band 8.5-9.5 GHz.},
	issn = {1531-1309},
	doi = {10.1109/LMWC.2010.2056358},
	url = {http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5545481},
	author = {Zhang, Y and J A Ruiz-Cruz and Zaki, K A and Piloto, A J}
}
@article {09_IJRFMiCAE_ZhangRuiz-CruzZaki_InlineandCanonical,
	title = {Inline and Canonical Stripline Filters with Ridge Coupling Sections for LTCC Applications},
	journal = {International Journal of RF and Microwave Computer-Aided Engineering},
	volume = {19},
	number = {3},
	year = {2009},
	month = {May},
	pages = {354-363},
	abstract = {Inline and canonical filters employing stripline resonators coupled by evanescent-mode ridge waveguide sections are presented. The proposed configurations are suitable choices for broadband chip filters integrated in printed circuit boards, especially for those with constraints on size and loss. Low temperature co-fired ceramic (LTCC) technology can be used to manufacture such filters. To validate the idea, prototypes of Chebyshev and elliptic function filters are designed following a systematic procedure. Stepped impedance stripline resonators are used in the Chebyshev filter to improve the spurious response. A novel canonical structure is presented for achieving high selectivity elliptic function filter responses. Rigorous mode matching method is applied to analyze and optimize all the filters, whose results are validated by commercial software.},
	keywords = {bandpass, Chebyshev filter, elliptic response, LTCC, ridge waveguide, stripline},
	issn = {1096-4290},
	doi = {10.1002/mmce.20354},
	url = {http://www3.interscience.wiley.com/cgi-bin/fulltext/121582207/PDFSTART},
	author = {Zhang, Y and J A Ruiz-Cruz and Zaki, K A}
}
@conference {08_URSIESP_Ruiz-CruzZhangMontejo-GaraiEtAl_Disenodefiltros,
	title = {Dise{\~n}o de filtros dual-mode longitudinales en gu{\'\i}a de onda rectangular},
	booktitle = {Proc. 2008 Simposium Nacional URSI (in Spanish)},
	year = {2008},
	month = {Sept.},
	pages = {1-4},
	abstract = {Dual-Mode filters are used in applications where low mass and volume are required. In this paper, the Computer Aided Design of a new rectangular waveguide filter structure is proposed for achieving the dual-mode operation. It preserves the longitudinal inline topology used in the classical circular waveguide configuration, which can provide quasi-elliptic function responses. However, it has no coupling or tuning screws and it is exclusively made up of sections of aligned rectangular waveguides. This leads to a very efficient full-wave analysis based on the Mode-Matching method. The proposed CAD is illustrated with a four order prototype, whose results are compared with other numerical technique.},
	url = {http://w3.iec.csic.es/ursi/paginas/index_congresosreali.htm},
	author = {J A Ruiz-Cruz and Zhang, Y and Montejo-Garai, J R and Rebollar, J M and Zaki, K A}
}
@conference {08_IMS_Ruiz-CruzZhangMontejo-GaraiEtAl_LongitudinalDual-ModeFilters,
	title = {Longitudinal Dual-Mode Filters in Rectangular Waveguide},
	booktitle = {2008 IEEE MTT-S International Microwave Symposium Digest},
	year = {2008},
	month = {June},
	pages = {631-634},
	abstract = {Dual-Mode filters are used in applications where low mass and volume are required. In this paper, the Computer Aided Design of a new rectangular waveguide filter structure is proposed for achieving the dual-mode operation. It preserves the longitudinal inline topology used in the classical circular waveguide configuration, which can provide quasi-elliptic function responses. However, it has no coupling or tuning screws and it is exclusively made up of sections of aligned rectangular waveguides. This leads to a very efficient full-wave analysis based on the Mode-Matching method. The proposed CAD is illustrated with a four order prototype, whose results are compared with other numerical technique.},
	keywords = {Dual-Mode cavities, elliptic filter response, rectangular waveguide filter},
	issn = {0149-645X},
	url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=4632911\&isnumber=4632906},
	author = {J A Ruiz-Cruz and Zhang, Y and Montejo-Garai, J R and Rebollar, J M and Zaki, K A}
}
@conference {07_IMS_ZhangZakiRuiz-CruzEtAl_AnalyticalSynthesisof,
	title = {Analytical Synthesis of Generalized Multi-band Microwave Filters},
	booktitle = {2007 IEEE MTT-S International Microwave Symposium Digest},
	year = {2007},
	month = {June},
	pages = {1273-1276},
	abstract = {An analytical procedure is presented for the synthesis of generalized multi-band filters. The procedure is applicable to both symmetric and asymmetric frequency responses and effective for any number of passbands and stopbands. An optimum equal-ripple performance is obtained in each passband and stopband. Prescribed real or complex transmission zeros can also be employed in the multi-band filtering function.},
	keywords = {band-pass filters, band-stop filters, generalized multiband microwave filters, microwave filtersfrequency responses, optimum equal-ripple performance, passbands, stopbands},
	issn = {0149-645X},
	doi = {10.1109/MWSYM.2007.380425},
	url = {http://ieeexplore.ieee.org/iel5/4263706/4263707/04264064.pdf?tp=\&isnumber=\&arnumber=4264064},
	author = {Zhang, Y and Zaki, K A and J A Ruiz-Cruz and Atia, A E}
}
@conference {07_IMS_Ruiz-CruzZhangRebollarEtAl_TEMMode-MatchingAnalysis,
	title = {TEM Mode-Matching Analysis of Multi-coupled Strip-line Filters},
	booktitle = {2007 IEEE MTT-S International Microwave Symposium Digest},
	year = {2007},
	month = {June},
	pages = {541-544},
	abstract = {The analysis of multi-coupled strip-line filters by the mode-matching method is studied for different input/output excitations. The aim is to compare the computational effort of two different options and to propose the most suitable formulation for the design of some strip-line filters. It is shown that a suitable segmentation of the structure is essential for obtaining good numerical results. In fact, if the optimum segmentation is selected, a mode-matching analysis using only TEM modes can resemble the full-wave response, with shorter computation time. Hence, this approach can be very useful in design and different examples are shown to validate it, using other numerical methods and measurements of a ten order filter.},
	keywords = {microwave filters, mode matching, multicoupled strip-line filter design, optimum structure segmentation, strip line filtersTEM mode-matching analysis},
	issn = {0149-645X},
	doi = {10.1109/MWSYM.2007.380546},
	url = {http://ieeexplore.ieee.org/iel5/4263706/4263707/04263871.pdf?tp=\&isnumber=\&arnumber=4263871},
	author = {J A Ruiz-Cruz and Zhang, Y and Rebollar, J M and Zaki, K A and Montejo-Garai, J R and Piloto, A J}
}
@article {07_IEEEMWCL_Ruiz-CruzZhangZakiEtAl_Ultra-WidebandLTCCRidge,
	title = {Ultra-Wideband LTCC Ridge Waveguide Filters},
	journal = {IEEE Microwave and Wireless Components Letters},
	volume = {17},
	number = {2},
	year = {2007},
	month = {Feb.},
	pages = {115-117},
	abstract = {The design and experimental validation of an ultra-wideband (UWB) filter in a low temperature co-fired ceramic (LTCC) is presented. The bandpass filter uses ridge waveguide resonators realized in LTCC by printing parallel planar conductors for the top and bottom walls and closely spaced metal filled vias for the lateral walls. Filter coupling scheme and stripline transitions are developed for the UWB requirement. The mode-matching method is used in their design. The LTCC via effect and the measurement setup are also addressed. Finally, experimental results of a nine-order filter (design passband from 3 to 9GHz) are presented},
	keywords = {band-pass filters, bandpass filter, filter coupling scheme, low temperature co fired ceramic, LTCC, metal filled vias, mode matching method, nine order filter, planar conductors, ridge waveguide filters, ridge waveguide resonators, ridge waveguides, stripline transitions, ultra wideband filter, waveguide filters3 to 9 GHz},
	issn = {1531-1309},
	doi = {10.1109/LMWC.2006.890333},
	url = {http://ieeexplore.ieee.org/iel5/7260/4079621/04079639.pdf?tp=\&isnumber=4079621\&arnumber=4079639\&punumber=7260},
	author = {J A Ruiz-Cruz and Zhang, Y and Zaki, K A and Piloto, A J and Tallo, J}
}
@conference {06_IMS_ZhangRuiz-CruzZaki_RidgeWaveguideCoupled,
	title = {Ridge Waveguide Coupled Stripline Resonator Filters and Multiplexers},
	booktitle = {2006 IEEE MTT-S International Microwave Symposium Digest},
	year = {2006},
	month = {June},
	pages = {681-684},
	abstract = {Stripline resonator bandpass filters with evanescent-mode coupling sections by ridge waveguides are introduced in this paper. Such filters have very compact cross sections, which makes them suitable choices for some integrated systems having cross section constraints. Low Temperature Co-fired Ceramic (LTCC) technology can be employed to build such filters for PCB systems. It is also possible to manufacture them in air-filled metallic structures. Two filter design examples by Mode Matching Method (MMM) are given in this paper. Stepped impedance line resonators are used in one example to improve the spurious. The presented filters can also be applied for multiplexer applications using stripline junctions. One diplexer design example for LTCC application is presented to show the feasibility.},
	issn = {0149-645X},
	doi = {10.1109/MWSYM.2006.249724},
	url = {http://ieeexplore.ieee.org/iel5/4014788/4014789/04014995.pdf?tp=\&isnumber=\&arnumber=4014995},
	author = {Zhang, Y and J A Ruiz-Cruz and Zaki, K A}
}
@conference {06_IMS_ZhangRuiz-CruzZaki_RidgeWaveguideDivider,
	title = {Ridge Waveguide Divider Junctions for Wide-Band Multiplexer Applications},
	booktitle = {2006 IEEE MTT-S International Microwave Symposium Digest},
	year = {2006},
	month = {June},
	pages = {1225-1228},
	abstract = {Ridge waveguide divider junctions are introduced and applied to wide-band multiplexer applications. A rigorous analysis and optimization process by mode matching method (MMM) is employed to design the junctions that yield low reflection coefficient in common port and almost equal transmission coefficients in the other two ports over a wide frequency band. Two design examples of wide-band diplexer and triplexer using such junctions are presented. All the components involved in the diplexer/triplexer designs are rigorously modeled and cascaded by MMM. Optimization procedures by MMM are also applied in these two designs to improve the performance. Multiplexers using such junctions can be built in either metallic form or low-temperature co-fired ceramic (LTCC) technology},
	keywords = {low-temperature co-fired ceramics, mode matching, mode matching method, multiplexing equipment, ridge waveguide divider junctions, ridge waveguides, waveguide junctionsLTCC technology, wide-band diplexer, wide-band multiplexer applications, wide-band triplexer},
	issn = {0149-645X},
	doi = {10.1109/MWSYM.2006.249431},
	url = {http://ieeexplore.ieee.org/iel5/4014788/4014789/04015143.pdf?tp=\&isnumber=\&arnumber=4015143},
	author = {Zhang, Y and J A Ruiz-Cruz and Zaki, K A}
}
@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 {05_IEEETMTT_Ruiz-CruzSabbaghZakiEtAl_Canonicalridgewaveguide,
	title = {Canonical ridge waveguide filters in LTCC or metallic resonators},
	journal = {IEEE Transactions on Microwave Theory and Techniques},
	volume = {53},
	number = {1},
	year = {2005},
	month = {Jan.},
	pages = {174-182},
	abstract = {A new physical realization of an elliptic function filter response is proposed for achieving compact size, wide bandwidth, wide spurious free stopband and high-selectivity performance. The filter configuration can be implemented in conventional waveguide technology or embedded in a multilayer low-temperature co-fired ceramic structure for integration with other circuitry in a chip module. The filter is analyzed using rigorous mode matching. To validate the concept, prototypes of four- and six-cavity elliptic filters are designed following a systematic procedure. Approximate synthesis is used to obtain initial dimensions of the filter and the desired optimum response is obtained by means of a final full-wave optimization. The results are verified with other numerical methods and with the measurements of a fourth-order waveguide filter.},
	keywords = {band-pass filters, canonical ridge waveguide filters, cavity resonator filters, ceramics, chip module, circuit optimisation, elliptic filters, elliptic function filter response, four cavity elliptic filters design, fourth order waveguide filter, full-wave optimization, metallic resonators, microwave filters, mode matching, multilayer low temperature cofired ceramic structure, multilayers, numerical methods, prototypes, resonators, ridge waveguides, six cavity elliptic filters design, spurious free stopband filter, waveguide filters band pass filters, waveguide technology},
	issn = {0018-9480},
	doi = {10.1109/TMTT.2004.839324},
	url = {http://ieeexplore.ieee.org/iel5/22/30125/01381687.pdf?tp=\&arnumber=1381687\&isnumber=30125},
	author = {J A Ruiz-Cruz and El Sabbagh, M A and Zaki, K A and Rebollar, J M and Zhang, Y}
}
@conference {05_APS_ZhangZakiRuiz-Cruz_Dualmodebandpass,
	title = {Dual mode bandpass filter with asymmetric transfer function},
	booktitle = {Proc. 2005 IEEE Antennas and Propagation Society International Symposium},
	volume = {2B},
	year = {2005},
	month = {July},
	pages = {634-637},
	abstract = {We demonstrate the feasibility of dual mode implementation of an asymmetric elliptic filter. A filter which has four poles and one transmission zero is synthesized from the general Chebyshev transfer function. The ideal electrical network of the longitudinal form is then obtained through several "rotation" operations on the initial coupling matrix. Finally, the dual mode circular waveguides are adopted to realize the ideal network.},
	keywords = {asymmetric elliptic filter, asymmetric transfer function, band-pass filters, Chebyshev filters, circular waveguides, coupling matrix, dual mode bandpass filter, dual mode circular waveguides, elliptic filters, ideal network, microwave filters, poles, poles and zeros, rotation operations, transfer function matrices, transmission zero, waveguide filters Chebyshev transfer function},
	issn = {0-7803-8884-4},
	doi = {10.1109/APS.2005.1552092},
	url = {http://ieeexplore.ieee.org/iel5/10402/33057/01552092.pdf?tp=\&isnumber=\&arnumber=1552092},
	author = {Zhang, Y and Zaki, K A and J A Ruiz-Cruz}
}
@conference {05_IMS_Ruiz-CruzZhangZakiEtAl_Ridgewaveguidebranch-line,
	title = {Ridge waveguide branch-line directional couplers for wideband applications and LTCC technology},
	booktitle = {2005 IEEE MTT-S International Microwave Symposium Digest},
	year = {2005},
	month = {June},
	pages = {1219-1222},
	abstract = {A new branch-line directional coupler is proposed for achieving wide bandwidth. The device is implemented in ridge waveguide to exploit its wide monomode band. It can be physically realized either in empty ridge waveguide or in LTCC for integration in a chip module. Two prototypes of two and five branches are designed following a systematic procedure. An appropriate equivalent circuit provides initial dimensions and the desired optimum response is obtained by means of a final full-wave optimization based on the rigorous and efficient mode-matching method. The results are verified with the finite element method of the HFSS software and a prototype will be manufactured for testing},
	keywords = {branch-line directional couplers, chip module integration, directional couplers, equivalent circuits, finite element analysis, finite element method, full-wave optimization, mode matching, mode-matching method, optimisation, ridge waveguides, ridge waveguidesLTCC technology, wide monomode band},
	issn = {01490-645X},
	doi = {10.1109/MWSYM.2005.1516896},
	url = {http://ieeexplore.ieee.org/iel5/10171/32491/01516896.pdf?tp=\&isnumber=\&arnumber=1516896},
	author = {J A Ruiz-Cruz and Zhang, Y and Zaki, K A and Piloto, A J and Rebollar, J M}
}
