@conference {20_EUCAP2020_ARRAY_DUAL_BOWTIE_EDUARDO, title = {Dual Circularly Polarized Waveguide Array Antenna Formed by Full-Metallic Bow-tie Radiating Cavities}, booktitle = {2020 14th European Conference on Antennas and Propagation (EuCAP)}, year = {2020}, month = {March}, pages = {1-5}, abstract = {A full-metallic dual circularly polarized antenna based on an array of bow-tie shaped radiating elements is presented in this contribution. The radiating element, formed by a bow-tie shaped cavity, can generate dual circular polarization. It is fed by a square waveguide path that supports the two degenerate modes TE10 and TE01. The excitation of the TE10 mode in the input port generates left-hand circular polarization while the TE01 mode generates right-hand circular polarization. Furthermore, a dual circularly polarized array antenna formed by bow-tie radiating elements has been designed. The two degenerate modes TE10 and TE01 are supported by a four-way feeding network implemented in square waveguide technology. Both the single radiating element and the dual circularly polarized array have been fabricated by CNC milling techniques. A pure circular polarization performance, high gain or high efficiency have been obtained, experimentally validating the dual circularly polarized bow-tie element in an array configuration.}, keywords = {antenna diversity, Aperture antennas, Dual-polarized antennas, waveguide arrays}, doi = {10.23919/EuCAP48036.2020.9135228}, author = {E Garcia-Marin and P Sanchez-Olivares and J L Masa-Campos and J A Ruiz-Cruz and J Herranz-Alpanseque} } @article {18_TAP_PABLO-SANCHEZ_WG-SLOT-ARRAY-TUNING-SCREWS, title = {Mechanical Technique to Customize a Waveguide-Slot Radiating Performance}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {66}, year = {2018}, pages = {426-431}, abstract = {A mechanical technique to tune the radiating performance of a waveguide-fed slot is presented. Three metallic tuning screws are introduced through the bottom wall of the feeding waveguide. The field radiated by the slot is mechanically controlled with the insertion length of the tuning screws and a good input matching response is also maintained. One of the tuning screws modifies the slot coupling parameter as well as the phase of the transmitted signal, while the other pair of screws compensates the impedance mismatch introduced by the first one. A five-element traveling-wave (TW) linear array antenna has been designed and manufactured as a proof of concept to validate the performance of the tuning screws. Several improvements such as a main beam steering range of 17{\textdegree}, an enhancement of the antenna efficiency, the mitigation of the undesirable grating lobe appearance typical of TW air-waveguide-fed arrays, as well as the compensation of the mutual coupling effects or manufacturing tolerance errors could be experimentally achieved by using the proposed mechanism based on tuning screws.}, keywords = {linear arrays, Slot antennas, waveguide arrays}, issn = {0018-926X}, doi = {10.1109/TAP.2017.2772078}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=8103014}, author = {P Sanchez-Olivares and J L Masa-Campos and J Hernandez-Ortega} } @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} } @article {17_TAP_PABLO-SANCHEZ_RECONF_RADIALWG_ARRAY, title = {Mechanically Reconfigurable Conformal Array Antenna Fed by Radial Waveguide Divider With Tuning Screws}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {65}, year = {2017}, pages = {4886-4890}, abstract = {A conformal array antenna with a reconfigurable radiation pattern in the azimuth plane at Ku band is presented. An eight-faced prism has been set as 3-D antenna structure. The radiating element consists of a rectangular waveguide ended on a slotted cavity. A radial waveguide network (RWGN) fed by a symmetrically placed coaxial probe has been implemented to equally feed each radiating element obtaining an omnidirectional behavior in the azimuth plane. The insertion of several metallic tuning screws (TSs) provides a reconfiguration mechanism of the electric field distribution in the RWGN and modifies the conformal array antenna amplitude feeding. Eight different configurations generating directional radiation patterns can be tuned by means of the insertion of certain TSs. In addition, the symmetrical positioning of them allows performing a main beam scanning every 45{\textdegree} in the azimuth plane. Several prototypes have been manufactured and measured to experimentally validate the antenna performance. A total of 65 different radiation patterns have been experimentally obtained using the proposed TSs, which provides a simple, low-loss, and low-cost reconfigurability mechanism to the presented conformal array antenna.}, keywords = {Conformal antenna, Slot antennas, waveguide arrays}, issn = {0018-926X}, doi = {10.1109/TAP.2017.2723918}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=7970137\&isnumber=8024125}, author = {P Sanchez-Olivares and J L Masa-Campos} }