Circularly polarized integrated filtering antenna with polarization reconfigurability

A new design of circularly polarized (CP) integrated filtering antennas with reconfigurable polarization is proposed in this paper. Two phase-reconfigurable coupled λ/2-resonator pairs have been used to feed the antenna and generate the 2nd-order filtering response and the circular polarization simultaneously. By switching the PIN diodes inserted in the feeding network, a phase difference of +90° or - 90° can be realized at the outputs of the feeding network. This renders the antenna’s capability of switching its polarization from right hand circular polarization (RHCP) to left hand circular polarization (LHCP) or vice versa. The use of the coupled-resonator pairs significantly improves the frequency selectivity and out-of-band rejection of the CP antenna. To the best of the authors’ knowledge, this is the first report of a multifunctional antenna which has integrated filtering performance, circular polarization and polarization reconfigurability. To verify the design concept, a reconfigurable CP antenna operating at 2.45 GHz is implemented. The simulated and measured results agree well with each other and show that the antenna has an impedance bandwidth of 4.5 %, an average in-band gain of 6.0 dBic (LHCP)/6.1 dBic (RHCP), out-of-band rejections of greater than 10.8 dB, and 3-dB AR bandwidth of 9.4 %/10.5 %

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

Connecting wearable textile transmission lines: all‐textile fabrication solutions and design techniques

This paper is a postprint of a paper submitted to and accepted for publication in Electronics Letters and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library.A new method for connecting transmission lines is presented without using rigid connectors in order to implement a fully textile interconnecting system appropriate for signal transmission in wearable applications. This method is applied to textile striplines and named ‘complementary overlap’. The proposed method is examined from 1 to 6 GHz covering the frequency bands of the target applications: ISM (WLAN, Bluetooth, ZigBee etc.) and L-band (GPS)

23:1 Bandwidth ratio quasi‐lumped component balun on a multilayer organic substrate

In this study, the authors present the design and development of a novel ultra-wideband coupled-line balun on a multilayer liquid crystal polymer substrate. The balun is designed using a quarter wavelength (λ/4) asymmetric broadside coupled line. The defected ground structure and a lumped phase compensation circuit are developed to achieve wide bandwidth performance for the balun. The balun has a measured bandwidth ratio of 23:1, from 80 to 1860 MHz. Within the operating bandwidth, the experimental results demonstrate that the balun achieves an input return loss of better than 10 dB, an insertion loss of better than 1 dB, an amplitude imbalance of better than ±0.4 dB and a phase imbalance of better than ±10°. The size of the balun is 40.64 mm × 40.64 mm or 0.22 λg × 0.22 λg, where λg is the guided wavelength at the centre frequency of 970 MHz

TOPLHA: an accurate and efficient numerical tool for analysis and design of LH antennas

This paper presents a self-consistent, integral-equation approach for the analysis of plasma-facing lower hybrid (LH) launchers; the geometry of the waveguide grill structure can be completely arbitrary, including the non-planar mouth of the grill. This work is based on the theoretical approach and code implementation of the TOPICA code, of which it shares the modular structure and constitutes the extension into the LH range. Code results are validated against the literature results and simulations from similar code

Optical guided dispersions and subwavelength transmissions in dispersive plasmonic circular holes

The light transmission through a dispersive plasmonic circular hole is numerically investigated with an emphasis on its subwavelength guidance. For a better understanding of the effect of the hole diameter on the guided dispersion characteristics, the guided modes, including both the surface plasmon polariton mode and the circular waveguide mode, are studied for several hole diameters, especially when the metal cladding has a plasmonic frequency dependency. A brief comparison is also made with the guided dispersion characteristics of a dispersive plasmonic gap [K. Y. Kim, et al., Opt. Express 14, 320-330 (2006)], which is a planar version of the present structure, and a circular waveguide with perfect electric conductor cladding. Finally, the modal behavior of the first three TM-like principal modes with varied hole diameters is examined for the same operating mode.Comment: 20 pages, 5 figures, 1 tabl