@conference {12_ESA_Montejo-GaraiRuiz-CruzRebollar_RecentResultsFiltersWBand,
	title = {Recent Results on Waveguide Filters at W-Band},
	booktitle = {Proc. 2012 ESA Microwave Technology and Techniques Workshop},
	year = {2012},
	month = {Nov.},
	pages = {1-6},
	author = {C A Leal-Sevillano and Montejo-Garai, J R and J A Ruiz-Cruz and Rebollar, J M}
}
@article {12_RS_Leal-SevillanoRuiz-CruzMontejo-GaraiEtAl_RigorousanalysisofParallelPlateTEMtoPolariton,
	title = {Rigorous analysis of the parallel plate waveguide: From the transverse electromagnetic mode to the surface plasmon polaritons},
	journal = {Radio Science},
	volume = {47},
	number = {RS0NO2},
	year = {2012},
	month = {February},
	pages = {1-8},
	abstract = {This paper presents an analysis of the parallel plate waveguide, based on a hybrid mode formulation. The nonideal metallic conductors of the waveguide are treated as a media characterized by an equivalent permittivity. The frequencies of interest in the presented analysis are at the terahertz band (from 300 GHz to 30 THz), and appropriate models are used for the correct characterization of metallic conductors at these frequencies. The behavior of the electromagnetic field of the fundamental mode is studied in a wide frequency range. At low frequencies (microwave regime) the fundamental mode is the well-known transverse electromagnetic (TEM) mode; as frequency increases, the electromagnetic field changes significantly and a surface wave or surface plasmon polariton (SPP) behavior is observed at the highest frequencies of the terahertz band. This paper shows a unified formulation that explains this transformation in the electromagnetic field behavior.},
	issn = {0018-9480},
	doi = {doi:10.1029/2011RS004838},
	url = {http://onlinelibrary.wiley.com/doi/10.1029/2011RS004838/pdf},
	author = {C A Leal-Sevillano and J A Ruiz-Cruz and Montejo-Garai, J R and Rebollar, J M}
}
@conference {11_URSIGAAS_Leal-SevillanoRuiz-CruzMontejo-GaraiEtAl_RigorousAnalysisofParallelPlate,
	title = {Rigorous Analysis of the Parallel-Plate Waveguide by the Hybrid Mode Formulation:From the TEM mode to the Surface Plasmon Polariton},
	booktitle = {Proc. 2011 URSIGAAS},
	year = {2011},
	month = {August},
	pages = {1-4},
	abstract = {This paper presets an analysis of the parallel-plate waveguide, based on an hybrid mode formulation. The nonideal metallic conductors of the waveguide are treated as a media characterized by an equivalent permittivity. The frequencies of interest in the presented analysis are at the terahertz band (from 300 GHz to 30 THz) and appropriate models are used for the correct characterization of metallic conductors at these frequencies. The behavior of the electromagnetic field of the fundamental mode is studied in a wide frequency range. At low frequencies (microwave regime) the fundamental mode is the well-known TEM mode; as frequency increases, the electromagnetic field changes significantly and a surface wave or Surface Plasmon Polariton (SPP) behavior is observed at the highest frequencies of the terahertz band. This paper shows an unified formulation that explains this transformation in the electromagnetic field behavior.},
	author = {C A Leal-Sevillano and J A Ruiz-Cruz and Montejo-Garai, J R and Rebollar, J M}
}
@conference {06_URSIUSA_Ruiz-CruzMontejo-GaraiRebollar_RelativeConvergenceProblem,
	title = {Relative Convergence Problem in the Mode-Matching Analysis of Stripline Interdigital Filters with Different Input-Output Coupling},
	booktitle = {Proc. 2006 USNC/URSI National Radio Science Meeting},
	year = {2006},
	month = {July},
	pages = {1},
	abstract = {Interdigital filters are used in microwave frequencies by their wide spurious-free response and their highly symmetric frequency response, which can be used to design filters with very flat group delay. They are TEM mode filters made up of a number of metallic rods or strips enclosed by a box and positioned consecutively along z-direction (see Fig. 1). The input/output of the filter can be transversal (Fig. 1.a) or longitudinal (Fig. 1.b) to the resonating strips, depending on the required interfaces and filter bandwidth. The approximate design of interdigital filters is found in Matthaei et al. classic book (Microwave Filters, Impedance-Matching Networks and Coupling Structures, Artech House, 1980). A full-wave analysis method is required in order to take into account parasitic effects of the physical implementation such as the coupling between non-adjacent lines or the enclosure box. This communication addresses the Mode-Matching analysis (MM) of the structures in Fig. 1, which is applied as follows. Firstly, the structure is segmented into a number of uniform waveguides along a specific direction (x in Fig.1.a and z in Fig. 1.b), whose TE, TM and TEM mode spectrum can be calculated either analytically or numerically. Secondly, the Generalized Scattering Matrix (GSM) that characterizes each basic step between two consecutive waveguides of different cross sections is calculated. Finally, all the individual GSMs are cascaded adequately to obtain the overall filter response. Although this procedure is applied to the configurations in Fig. 1, its implementation leads to significant numerical differences for the structures with perpendicular (along x) and longitudinal (along z) excitation. Basically, the analysis in Fig.1.a involves TEMx modes, which model the total field in the structure adequately. However, the field in the resonators in Fig.1.b is obtained by summing up TEz and TMz modes, which leads to convergence difficulties. The results of the investigated relative convergence problems [T. Itoh, Numerical Techniques {\^a}{\texteuro}{\textbrokenbar}, John Wiley, 1989] will be shown in the oral presentation.},
	author = {J A Ruiz-Cruz and Montejo-Garai, J R and Rebollar, J M}
}
@conference {05_IMS_Ruiz-CruzZakiMontejo-GaraiEtAl_Rectangularwaveguideelliptic,
	title = {Rectangular waveguide elliptic filters with capacitive and inductive irises and integrated coaxial excitation},
	booktitle = {2005 IEEE MTT-S International Microwave Symposium Digest},
	year = {2005},
	month = {June},
	pages = {269-272},
	abstract = {CAD of rectangular waveguide filters with elliptic responses is described. The configuration uses capacitive and inductive irises in order to achieve the different coupling signs required to synthesize finite transmission zeros in the rejection bands. The input and output ports are realized by a coaxial probe that directly excites the input/output cavities. The analysis is done by the efficient mode-matching method, in order to allow a final full-wave optimization taking into account all the higher order mode interactions. The CAD results are verified with the HFSS and a filter was manufactured for testing.},
	keywords = {band-stop filters, capacitive iris, circuit CAD, coaxial probe, coaxial waveguides, elliptic filters, finite transmission zeros, full-wave optimization, higher order mode interactions, inductive iris, input ports, integrated coaxial excitation, mode matching, mode-matching method, optimisation, output ports, rectangular waveguide filter, rectangular waveguides, rejection bands, waveguide filters CAD},
	issn = {01490-645X},
	doi = {10.1109/MWSYM.2005.1516577},
	url = {http://ieeexplore.ieee.org/iel5/10171/32491/01516577.pdf?tp=\&isnumber=\&arnumber=1516577},
	author = {J A Ruiz-Cruz and Zaki, K A and Montejo-Garai, J R and Rebollar, J M}
}
