@article {12_IEEEMWCL_Leal-SevillanoMontejo-GaraiRuiz-CruzEtAl_Low-LossEllipticalResponse, title = {Low-Loss Elliptical Response Filter at 100 GHz}, journal = {Microwave and Wireless Components Letters, IEEE}, volume = {22}, number = {9}, year = {2012}, month = {September}, pages = {459 -461}, abstract = {The design, method of fabrication and experimental validation of a pseudo-elliptical four-poles asymmetric response filter at 100 GHz with 10\% of fractional bandwidth is presented. The designed filter is part of an image radar system and must fulfill stringent specifications. The proposed topology and method of fabrication improves the out of band rejection above the pass band in comparison with other classical structures, while keeping a low insertion loss level. A two-fold geometry for implementing a transmission zero is proposed, avoiding the excitation of the first higher order mode and easing the manufacturing without any tuning element. A low-cost milling process is used for the fabrication of the device. The final design fulfills the desired specifications and presents 0.6 dB of insertion loss level at 100 GHz. The excellent agreement between simulations and measurements at this frequency band in both, return loss and insertion loss, is pointed out.}, keywords = {Asymmetric, band-pass filters, elliptic filters, extracted pole, Fabrication, fabrication method, filter, filtering theory, fractional bandwidth, frequency 100 GHz, higher order mode, image radar system, Insertion loss, loss 0.6 dB, Loss measurement, low insertion loss level, low loss, low-cost milling process, low-loss elliptical response filter, microwave filters, millimetre wave filters, Milling, out of band rejection, pseudo-elliptical four-poles asymmetric response filter, Radar, return loss, transmission zero, two-fold geometry, W-band}, issn = {1531-1309}, doi = {10.1109/LMWC.2012.2212237}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6268297\&tag=1}, author = {C A Leal-Sevillano and Montejo-Garai, J R and J A Ruiz-Cruz and Rebollar, J M} } @article {05_IEEETMTT_Montejo-GaraiRuiz-CruzRebollarEtAl_Synthesisanddesign, title = {Synthesis and design of in-line N-order filters with N real transmission zeros by means of extracted poles implemented in low-cost rectangular H-plane waveguide}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {53}, number = {5}, year = {2005}, month = {May}, pages = {1636-1642}, abstract = {In this paper, an extension to the extracted pole technique for synthesizing N-order filters with N-transmission zeros at real frequencies is presented. In addition, a new bandpass rectangular waveguide H-plane low-cost configuration filter for high-power low-loss application (patent pending) that implements a filtering function with finite real frequency transmission zeros is proposed. This structure operates as a resonant cavity in transmission at central frequency of the bandpass and simultaneously introduces a controlled transmission zero out of the bandpass. Since every double-controlled electrical behavior cavity introduces a transmission zero, it is possible to introduce as many transmission zeros as the order of the filtering function. In order to validate the synthesis procedure and the new structure, different filters have been designed: a second-order filter with two transmission zeros, a third-order filter with one transmission zero, a fourth-order filter with two transmission zeros, and finally, an eighth-order filter with two transmission zeros. The last two have been manufactured, showing an excellent agreement between the measurement and theoretical simulation.}, keywords = {band-pass filters, double-controlled electrical behavior cavity, eighth-order filter, extracted pole technique, filter synthesis, filtering function, finite real frequency transmission zeros, fourth-order filter, in-line N-order filters, network synthesis, planar waveguides, poles and zeros, rectangular H-plane waveguide, rectangular waveguides, resonant cavity, second-order filter, third-order filter, waveguide filters bandpass rectangular waveguide H-plane filter}, issn = {0018-9480}, doi = {10.1109/TMTT.2005.847053}, url = {http://ieeexplore.ieee.org/iel5/22/30829/01427966.pdf?tp=\&isnumber=\&arnumber=1427966}, author = {Montejo-Garai, J R and J A Ruiz-Cruz and Rebollar, J M and Padilla-Cruz, M J and Onoro-Navarro,A and Hidalgo-Carpintero, I} } @conference {02_APS_Ruiz-CruzMontejo-GaraiRebollar_Characterisationofwaveguide, title = {Characterisation of waveguide discontinuities with finite wall conductivity}, booktitle = {Proc. 2002 IEEE Antennas and Propagation Society International Symposium}, volume = {4}, year = {2002}, month = {June}, pages = {428-431}, abstract = {In this paper, a procedure is proposed to evaluate the generalised scattering matrix of waveguide discontinuities with finite wall conductivity. This approach is applied to evaluate the insertion losses in several waveguide structures of Chebyshev bandpass filters. These numerical results are compared with those obtained with other numerical methods and with measurements, validating the proposed procedure.}, keywords = {band-pass filters, Chebyshev filters, electromagnetic wave scattering, finite wall conductivity, generalised scattering matrix, insertion losses, numerical methods, S-matrix theory, waveguide discontinuities, waveguide filters, waveguide theory Chebyshev bandpass filters}, issn = {0-7803-7330-8}, doi = {10.1109/APS.2002.1017013}, url = {http://ieeexplore.ieee.org/iel5/7931/21884/01017013.pdf?tp=\&isnumber=\&arnumber=1017013}, author = {J A Ruiz-Cruz and Montejo-Garai, J R and Rebollar, J M} }