Electromagnetic vacuum energy for two parallel slabs in terms of surface, wave guide and photonic modes

The formulation of the Lifshitz formula in terms of real frequencies is reconsidered for half spaces described by the plasma model. It is shown that besides the surface modes (for the TM polarization), and the photonic modes, also waveguide modes must be considered.Comment: some references adde

Investigation into use of double-layer grid structures as frequency selective surfaces for buildings

A simple Double–Layer Grid plane wave filter structure is proposed that can provide multiple transmission bands for cellular phone frequencies but with a reflection band for WLAN signals. The approach offers ease of construction making it applicable to building applications. A parametric study using simulation supported by simple experimental data investigates the proposed, novel desig

Miniaturized dielectric waveguide filters

Design techniques for a new class of integrated monolithic high-permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled transverse electromagnetic filters with the same unloaded Q-factor. Designs for Chebyshev and asymmetric generalised Chebyshev filter and a diplexer are presented with experimental results for an 1800 MHz Chebyshev filter and a 1700 MHz generalised Chebyshev filter showing excellent agreement with theory

OPTIMIZATION ISSUES IN FINITE ELEMENT CODES FOR SOLVING OPEN DOMAIN 3D ELECTROMAGNETIC SCATTERING AND CONFORMAL ANTENNA PROBLEMS

The first part of the paper presents the implementation and performance of a new absorbing boundary condition (ABC) for truncating finite element meshes. This ABC can be applied conformally to the surface of the structure for scattering and antenna radiation calculations. Consequently, the computational domain is reduced dramatically, thus allowing the simulation of much larger structures, and results are presented for three-dimensional bodies. The latter part of the paper discusses optimization issues relating to the solver's CPU speed on parallel and vector processors. It is shown that a jagged diagonal storage scheme leads to a four-fold increase in the FLOP rate of the code, and a standard matrix profile reduction algorithm substantially reduces the inter-processor communication.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50414/1/241_ftp.pd

Properties of a Variable-delay Polarization Modulator

We investigate the polarization modulation properties of a variable-delay polarization modulator (VPM). The VPM modulates polarization via a variable separation between a polarizing grid and a parallel mirror. We find that in the limit where the wavelength is much larger than the diameter of the metal wires that comprise the grid, the phase delay derived from the geometric separation between the mirror and the grid is sufficient to characterize the device. However, outside of this range, additional parameters describing the polarizing grid geometry must be included to fully characterize the modulator response. In this paper, we report test results of a VPM at wavelengths of 350 microns and 3 mm. Electromagnetic simulations of wire grid polarizers were performed and are summarized using a simple circuit model that incorporates the loss and polarization properties of the device.Comment: 25 pages, 10 figures, accepted by Applied Optic

Systematic Procedure to Avoid Unintended Polarity Mismatch in the Cascade Connection of Multiport Devices with Symmetric Feeding Lines

This paper is a postprint of a paper submitted to and accepted for publication in [journal] and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital LibraryThe traditional cascading of generalised scattering matrices (GSMs) assumes that the modal sets at the connected ports of a cascaded network are strictly equal. This implies a careful selection of the modal polarities, or the reference systems, of every port. Usually, the connection scheme of every device is known a priori. Then, the individual GSMs are pre-processed, or auxiliary devices, which correct possible modal mismatches at the ports, are included in appropriate positions among the cascade, so that the traditional cascading-by-pairs approach can be directly applied. This scheme clearly complicates the reutilisation of previously calculated GSMs, and mixes the cascading with the solution of the individual building blocks. In this study, a systematic procedure is proposed to define the polarity of the modes at the ports of a device fed with transmission lines or waveguides showing a single or double symmetry. The modified expressions to calculate the scattering parameters of the cascade of two multiport devices, incorporating the regular modal corrections to apply when this criterion is used to define the modal polarity at the ports, is also presented in this study. This strategy is more convenient from the point of view of programming, less error-prone and easier to implement.This work was supported by the Ministry of Science and Innovation, Spanish Government, under Research Projects TEC2013-47037-C05-3-R and TEC2013-47037-C05-1-R.Belenguer Martínez, Á.; Borja, A.; Díaz Caballero, E.; Esteban González, H.; Boria Esbert, VE. (2015). Systematic Procedure to Avoid Unintended Polarity Mismatch in the Cascade Connection of Multiport Devices with Symmetric Feeding Lines. IET Microwaves Antennas and Propagation. 9(11):1128-1135. https://doi.org/10.1049/iet-map.2014.0167S1128113591

Direct optoelectronic generation and detection of sub-ps-electrical pulses on sub-mm-coaxial transmission lines

We report efficient direct optoelectronic generation of sub-ps-THz pulses on 50 Ohm coaxial transmission lines with a 330 micro-m diameter solid copper outer tube filled with Teflon containing the 80 micro-m diameter inner conductor. The transmitted pulses after propagating as much as 105 mm were measured at the end of the line with an optoelectronic antenna having sub-ps-time resolution. We observed low-loss, single transverse electromagnetic mode propagation with very little group velocity dispersion. The experimentally derived values for the frequency-dependent absorption are consistent with the theoretical predictions.Peer reviewedElectrical and Computer Engineerin

The Planck-LFI flight model composite waveguides

The Low Frequency Instrument on board the PLANCK satellite is designed to give the most accurate map ever of the CMB anisotropy of the whole sky over a broad frequency band spanning 27 to 77 GHz. It is made of an array of 22 pseudo-correlation radiometers, composed of 11 actively cooled (20 K) Front End Modules (FEMs), and 11 Back End Modules (BEMs) at 300K. The connection between the two parts is made with rectangular Wave Guides. Considerations of different nature (thermal, electromagnetic and mechanical), imposed stringent requirements on the WGs characteristics and drove their design. From the thermal point of view, the WG should guarantee good insulation between the FEM and the BEM sections to avoid overloading the cryocooler. On the other hand it is essential that the signals do not undergo excessive attenuation through the WG. Finally, given the different positions of the FEM modules behind the focal surface and the mechanical constraints given by the surrounding structures, different mechanical designs were necessary. A composite configuration of Stainless Steel and Copper was selected to satisfy all the requirements. Given the complex shape and the considerable length (about 1.5-2 m), manufacturing and testing the WGs was a challenge. This work deals with the development of the LFI WGs, including the choice of the final configuration and of the fabrication process. It also describes the testing procedure adopted to fully characterize these components from the electromagnetic point of view and the space qualification process they underwent. Results obtained during the test campaign are reported and compared with the stringent requirements. The performance of the LFI WGs is in line with requirements, and the WGs were successfully space qualified.Comment: this paper is part of the Prelaunch status LFI papers published on JINST: http://www.iop.org/EJ/journal/-page=extra.proc5/jins

Novel spatial domain integral equation formulation for the analysis of rectangular waveguide steps close to arbitrarily shaped dielectric and/or conducting posts

[EN] In this paper, a novel integral equation formulation expressed in the spatial domain is proposed for the analysis of rectangular waveguide step discontinuities. The important novelty of the proposed formulation is that which allows to easily take into account the electrical influence of a given number of arbitrarily shaped conducting and dielectric posts placed close to the waveguide discontinuity. For the sake of simplicity, and without loss of generality, the presented integral equation has been particularized and solved for inductive rectangular waveguide geometry. In this case, the integral equation mixed-potentials kernel is written in terms of parallel plate Green¿s functions with an additional ground plane located on the waveguide step. Therefore, the unknowns of the problem are reduced to an equivalent magnetic surface current on the step aperture and equivalent magnetic and electric surface currents on the dielectric and conducting posts close to the discontinuity. The numerical solution of the final integral equation is efficiently computed after the application of acceleration techniques for the slowly convergent series representing the Green¿s functions of the problem. The numerical method has been validated through several simulation examples of practical microwave devices, including compact size band-pass cavity filters and coupled dielectric resonators filters. The results have been compared to those provided by commercial full-wave electromagnetic simulation software packages, showing in all cases a very good agreement, and with substantially enhanced numerical efficiencies.This research work has been financially supported by the Spanish Ministerio de Economia y Competitividad in the frame of the projects "Demostradores Tecnologicos de Filtros y Multiplexores con Respuestas Selectivas y Sintonizables en Nuevas Guias Compactas para Aplicaciones Espaciales (COMPASSES)" with Ref. TEC2016-75934-C4-1-R, and "Analisis y Diseno de Nuevos Componentes en Microondas y Milimetricas para Comunicaciones por Satelite (MILISAT)" with Ref. TEC2016-75934-C4-4-R. As an additional financial source we thank the regional agency Fundacion Seneca from Region de Murcia under the research project "Desarrollo de Antenas y Componentes Pasivos de Microondas para Sistemas Avanzados de Comunicaciones" with Ref. 19494/PI/14 and Ref. 20147/EE/17, and the PhD scholarship granted by the Spanish national Ministerio de Educacion, Cultura y Deporte with Ref. FPU15/02883. All results of this paper can be reproduced by using the data and information contained in the drawings and in the captions of the figures included in the paper.Quesada Pereira, FD.; Gomez Molina, C.; Alvarez Melcon, A.; Boria Esbert, VE.; Guglielmi, M. (2018). Novel spatial domain integral equation formulation for the analysis of rectangular waveguide steps close to arbitrarily shaped dielectric and/or conducting posts. Radio Science. 53(4):406-419. https://doi.org/10.1002/2017RS006429S406419534Arcioni , P. Bressan , M. Conciauro , G. Perregrini , L. 1997 Generalized Y-matrix of arbitrary H-plane waveguide junctions by the BI-RME method IEEE MTT-S International Microwave Symposium Digest 211 214 DenverCapolino, F., Wilton, D. R., & Johnson, W. A. (2005). Efficient computation of the 2-D Green’s function for 1-D periodic structures using the Ewald method. IEEE Transactions on Antennas and Propagation, 53(9), 2977-2984. doi:10.1109/tap.2005.854556Catina, V., Arndt, F., & Brandt, J. (2005). Hybrid surface integral-equation/mode-matching method for the analysis of dielectric loaded waveguide filters of arbitrary shape. IEEE Transactions on Microwave Theory and Techniques, 53(11), 3562-3567. doi:10.1109/tmtt.2005.857343Fructos, A. L., Boix, R. R., Mesa, F., & Medina, F. (2008). An Efficient Approach for the Computation of 2-D Green’s Functions With 1-D and 2-D Periodicities in Homogeneous Media. IEEE Transactions on Antennas and Propagation, 56(12), 3733-3742. doi:10.1109/tap.2008.2007281Guglielmi, M., & Newport, C. (1990). Rigorous, multimode equivalent network representation of inductive discontinuities. IEEE Transactions on Microwave Theory and Techniques, 38(11), 1651-1659. doi:10.1109/22.60012Hu, Y. L., Li, J., Ding, D. Z., & Chen, R. S. (2016). Analysis of Transient EM Scattering From Penetrable Objects by Time Domain Nonconformal VIE. IEEE Transactions on Antennas and Propagation, 64(1), 360-365. doi:10.1109/tap.2015.2501437Kalantari, M., & Paran, K. (2017). Analysing Metamaterial Layer by Simpler Approach Based on Mode Matching Technique. IET Microwaves, Antennas & Propagation, 11(5), 607-616. doi:10.1049/iet-map.2016.0687Mrvić, M., Potrebić, M., & Tošić, D. (2016). CompactEplane waveguide filter with multiple stopbands. Radio Science, 51(12), 1895-1904. doi:10.1002/2016rs006169Pérez-Soler, F. J., Quesada-Pereira, F. D., Cañete Rebenaque, D., Pascual-García, J., & Alvarez-Melcon, A. (2007). Efficient integral equation formulation for inductive waveguide components with posts touching the waveguide walls. Radio Science, 42(6). doi:10.1029/2006rs003591POGGIO, A. J., & MILLER, E. K. (1973). Integral Equation Solutions of Three-dimensional Scattering Problems. Computer Techniques for Electromagnetics, 159-264. doi:10.1016/b978-0-08-016888-3.50008-8Quesada Pereira , F. Boria , V. E. Gimeno , B. Cañete Rebenaque , D. Pascual Garcia , J. Alvarez Melcon , A. 2006 Investigation of multipaction phenomena in inductively coupled passive waveguide components for space applications IEEE MTT-S International Microwave Symposium Digest 246 249 San Francisco, CAPereira, F. D. Q., Esbert, V. E. B., Garcia, J. P., Ana Vidal Pantaleoni, Melcon, A. A., Tornero, J. L. G., & Gimeno, B. (2007). Efficient Analysis of Arbitrarily Shaped Inductive Obstacles in Rectangular Waveguides Using a Surface Integral-Equation Formulation. IEEE Transactions on Microwave Theory and Techniques, 55(4), 715-721. doi:10.1109/tmtt.2007.893673Quesada Pereira, F. D., Vera Castejón, P., Álvarez Melcón, A., Gimeno, B., & Boria Esbert, V. E. (2011). An efficient integral equation technique for the analysis of arbitrarily shaped capacitive waveguide circuits. Radio Science, 46(2), n/a-n/a. doi:10.1029/2010rs004458Stumpf, M., & Leone, M. (2009). Efficient 2-D Integral Equation Approach for the Analysis of Power Bus Structures With Arbitrary Shape. IEEE Transactions on Electromagnetic Compatibility, 51(1), 38-45. doi:10.1109/temc.2008.2009223Wei, X.-C., Li, E.-P., Liu, E.-X., & Cui, X. (2008). Efficient Modeling of Rerouted Return Currents in Multilayered Power-Ground Planes by Using Integral Equation. IEEE Transactions on Electromagnetic Compatibility, 50(3), 740-743. doi:10.1109/temc.2008.924392Huapeng Zhao, En-Xiao Liu, Jun Hu, & Er-Ping Li. (2014). Fast Contour Integral Equation Method for Wideband Power Integrity Analysis. IEEE Transactions on Components, Packaging and Manufacturing Technology, 4(8), 1317-1324. doi:10.1109/tcpmt.2014.232724

Empty substrate integrated waveguide technology for E plane high-frequency and high-performance circuits

Substrate integrated circuits (SIC) have attracted much attention in the last years because of their great potential of low cost, easy manufacturing, integration in a circuit board, and higher-quality factor than planar circuits. A first suite of SIC where the waves propagate through dielectric have been first developed, based on the well-known substrate integrated waveguide (SIW) and related technological implementations. One step further has been made with a new suite of empty substrate integrated waveguides, where the waves propagate through air, thus reducing the associated losses. This is the case of the empty substrate integrated waveguide (ESIW) or the air-filled substrate integrated waveguide (air-filled SIW). However, all these SIC are H plane structures, so classical H plane solutions in rectangular waveguides have already been mapped to most of these new SIC. In this paper a novel E plane empty substrate integrated waveguide (ESIW-E) is presented. This structure allows to easily map classical E plane solutions in rectangular waveguide to this new substrate integrated solution. It is similar to the ESIW, although more layers are needed to build the structure. A wideband transition (covering the frequency range between 33 GHz and 50 GHz) from microstrip to ESIW-E is designed and manufactured. Measurements are successfully compared with simulation, proving the validity of this new SIC. A broadband high-frequency phase shifter (for operation from 35 GHz to 47 GHz) is successfully implemented in ESIW-E, thus proving the good performance of this new SIC in a practical application.This work was supported by the Ministerio de Economía y Competitividad, Spanish Goverment, under research projects TEC2013-47037-C5-3-R, TEC2013-47037-C5-1-R, AYA2013-49759-EXP, and CSD2010-00064