@article {11145284,
	title = {Transfer ABCD Matrix for Time-Varying Media and Time Crystals},
	journal = {IEEE Transactions on Antennas and Propagation},
	volume = {73},
	number = {12},
	year = {2025},
	pages = {10931-10936},
	keywords = {ABCD parameters, Microwave amplifiers, Microwave communication, microwave filters, Microwave theory and techniques, Microwave transistors, network analysis, Nonhomogeneous media, Power transmission lines, S-matrix, scattering parameters, Slabs, temporal slabs, time crystal, Time-varying systems, Transmission line matrix methods},
	doi = {10.1109/TAP.2025.3602115},
	author = {Molero, Carlos and Zapata-Cano, Pablo. H. and Alex-Amor, Antonio}
}
@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 {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}
}
@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}
}
@conference {06_EuMC_Montejo-GaraiRuiz-CruzRebollarEtAl_DesignofSelf-Equalised,
	title = {Design of Self-Equalised Elliptic Filter Channels in Ka-Band Implemented in Rectangular H-Plane Waveguide},
	booktitle = {Proc. 36th European Microwave Conference},
	year = {2006},
	month = {Sept.},
	pages = {1087-1090},
	abstract = {In this article, a systematic design procedure for the design of self-equalised elliptic filters in H-plane configuration is presented. Such a configuration in tends to be an alternative to the classical dual-mode circular waveguide configuration in Ka band, with the aim in mind of reducing cost and computation time. In order to decrease the insertion loss the TE105 will be used. A sixth order filter with two transmission zeros at finite real frequencies and two zeros for equalisation has been designed, manufactured and measured. The results make clear the validity of the proposed configuration},
	keywords = {dual mode circular waveguide, elliptic filter channels, elliptic filters, Ka-band, microwave filters, Milling, mode matching, poles and zeros, rectangular waveguide, rectangular waveguides, self-equalised filter, systematic design procedure, waveguide filtersH-plane configuration},
	issn = {2-9600551-6-0},
	doi = {10.1109/EUMC.2006.281123},
	url = {http://ieeexplore.ieee.org/iel5/4057701/4057702/04058013.pdf?tp=\&isnumber=\&arnumber=4058013},
	author = {Montejo-Garai, J R and J A Ruiz-Cruz and Rebollar, J M and Onoro-Navarro, A. and Hidalgo-Carpintero, I and Padilla-Cruz, M J}
}
@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}
}
