This letter presents the design methodology of a textile rectangular patch antenna with increased bandwidth. The broadening of the antenna operating band is obtained by using a proximity coupling feed line cascaded to a quarter‐wave impedance transformer. The design parameters used to enhance the antenna bandwidth are the widths of the feed line and impedance transformer. The proposed design procedure has been applied to the design of four antennas centered at 2.45 GHz using denim substrate and conductive fabric. All antennas have the same patch dimensions, but they were designed using different values for the widths of the feed line and impedance transformer. The measured 10‐dB return loss bandwidth of the antenna prototypes are 11.2%, 13.4%, 17.0%, and 24.0%, in good agreement with simulated results. The effect of human body proximity and antenna curvature on the performance of the designed antennas has also been analyzed. The antenna configuration investigated has demonstrated to be able to increase the antenna operating band. The proposed design procedure is flexible, allowing the design of antennas with a variety of bandwidth values. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1906–1912, 2016

In this article, a novel mobile handset planar inverted-F antenna (PIFA) for tri-band operation in GSM, DCS, and PCS bands is presented. This PIFA comprises a rectangular folded planar radiator, which has a J-shaped slot, suspended above a partially grounded substrate. In this antenna, two resonant modes are excited and originate a lower band for GSM and an upper band for DCS and PCS. The influence of several geometrical parameters of the antenna on its performance was investigated to achieve an optimal design. The fabricated prototype of the proposed PIFA has overall dimensions of 45 Â 90 Â 6.6 mm 3 . The measured 10 dB return loss bands of the antenna are 880-892 MHz and 1658-2079 MHz. V C 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:821-825, 2013; View this article online at wileyonlinelibrary.com.ABSTRACT: This paper describes the development and performance of a 2 by 4 element suspended microstrip patch antenna array with linear

This article presents a transmission‐line‐based 3‐dB dual‐band branch‐line coupler. The coupler is easily realizable for ratios between the upper and lower operating frequencies ranging from 1.270 to 2.628. This means that it can be designed for two operation frequencies that are closer to each other in comparison with existing simple circuit topologies based on transmission lines, when considering a compact design. The complete set of equations for all possible responses of this dual‐band 90° hybrid coupler is derived. To evaluate its practical feasibility, the proposed circuit is analyzed with respect to the characteristic impedances of its transmission lines. A step‐by‐step procedure is presented to help the circuit designer deal with the use of the equations and all their degrees of freedom. For experimental validation, a microstrip dual‐band branch‐line coupler has been designed for operation at 3.835 and 5.285 GHz. A good agreement is observed between simulated and measured results.

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