@article {13_IEEETHz_Leal-SevillanoCooperRuiz-CruzEtAl_225GHzCircularPolDuplexer,
	title = {A 225 GHz Circular Polarization Waveguide Duplexer Based on a Septum Orthomode Transducer Polarizer},
	journal = {IEEE Transactions on Terahertz Science and Technology},
	volume = {3},
	number = {5},
	year = {2013},
	month = {Sep.},
	pages = {574-583},
	abstract = {In this paper, we present the modeling and experimental validation of an efficient, compact, and high-isolation waveguide duplexer operating at 225 GHz. While duplexers based on ferrite circulators are key components of many monostatic radar systems, at W-band frequencies and above the performance of waveguide circulators rapidly deteriorates. The design presented here uses a ferrite-free duplexing concept based on transmitting and receiving in orthogonal circular polarizations. The circular polarization is efficiently generated in waveguide using a septum orthomode transducer polarizer, leading to a compact device with a single horn antenna. The complete duplexer is designed using efficient numerical algorithms, resulting in a fabricated device with a measured 10\% fractional bandwidth, a return loss better than 20 dB, isolation of 30 dB, and insertion loss below 1 dB.},
	keywords = {Circular polarization, duplexer, orthomode transducer, terahertz},
	issn = {2156-342X},
	doi = {10.1109/TTHZ.2013.2264317},
	url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=6525512},
	author = {C A Leal-Sevillano and Cooper, K B and J A Ruiz-Cruz and Montejo-Garai, J R and Rebollar, J M}
}
@article {13_IEEEMWCL_Leal-SevillanoReckJung-KubiakEtAl_SiliconMicromachinedCanonicalTHz,
	title = {Silicon Micromachined Canonical E-Plane and H-Plane Bandpass Filters at the Terahertz Band},
	journal = {IEEE Microwave and Wireless Components Letters},
	volume = {23},
	number = {6},
	year = {2013},
	month = {June},
	pages = {288-290},
	abstract = {In this letter, several bandpass filters operating in the WR-1.5 band (500 to 750 GHz) are presented. The deep reactive ion etching (DRIE) silicon micromachining process is used for the fabrication of the filters. Two canonical filter topologies based on E- and H-plane are implemented. The work presented here has two specific objectives: a) to get important fabrication process parameters, such as tolerances, vertical angles, surface roughness, and repeatability and b) to validate the proper working of the waveguide filters in the terahertz band. These filters do not have any tuning element. Experimental results show better than 10 dB return loss and approximately 1 and 2.5 dB insertion loss (for 6\% fractional bandwidth) for the E- and H-plane topology, respectively. The obtained results are in agreement with fabrication tolerances of 2 micrometers and vertical angles deviations up to 3{\^A}{\textdegree}.},
	keywords = {Deep reactive ion etching (DRIE), filter, micromachining, terahertz, WR-15},
	issn = {1531-1309},
	doi = {10.1109/LMWC.2013.2258097},
	url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6509458},
	author = {C A Leal-Sevillano and Reck, T J and Jung-Kubiak, C and Chattopadhyay, G. and J A Ruiz-Cruz and Montejo-Garai, J R and Rebollar, J M}
}
@article {11_IEEETMTT_Leal-SevillanoRuiz-CruzMontejo-GaraiEtAl_FieldCircularHollowWgNonIdealConductorsMwtoThz,
	title = {Field Propagation in Circular Hollow Waveguides with Non-Ideal Metallic Conductors from Microwaves to Terahertz Frequencies},
	journal = {IEEE Transactions on Microwave Theory and Techniques},
	volume = {59},
	number = {12},
	year = {2011},
	month = {Dec},
	pages = {3013-3022},
	abstract = {A general and rigorous formulation is proposed for the analysis of hollow metallic waveguides from the gigahertz to the terahertz band. The analysis is based on a hybrid mode formulation and the Drude model for the dielectric permittivity of metallic conductors. The obtained results for the circular waveguide are compared with the classical microwave approach (surface impedance approximation or Leontovich condition). The validity range of the surface impedance approximation in both the propagation constant and the electromagnetic field pattern is studied. As a consequence, a direct relation between the error in the propagation constant and the electromagnetic field configuration is shown. Moreover, this formulation shows the evolution in the field pattern: from TE=TM modes at microwaves to the so-called Surface Plasmon Polariton at terahertz frequencies},
	keywords = {Drude, hybrid mode, Leontovich, modal solution, surface impedance, Surface Plasmon Polariton (SPP), surface wave, terahertz, waveguides},
	issn = {0018-9480},
	url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6065772\&tag=1},
	author = {C A Leal-Sevillano and J A Ruiz-Cruz and Montejo-Garai, J R and Rebollar, J M}
}
