Topic
Return loss
About: Return loss is a research topic. Over the lifetime, 11090 publications have been published within this topic receiving 97603 citations.
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TL;DR: In this paper, a 2D electronically steered phased-array antenna with a liquid-crystal (LC)-based variable delay line is presented, which consists of a 2 × 2 microstrip patch antenna array, continuously variable delay lines with a novel geometry, RF feeding and biasing networks.
Abstract: For the first time, a 2-D electronically steered phased-array antenna with a liquid-crystal (LC)-based variable delay line is presented. The structure, which is designed at 17.5 GHz, consists of a 2 × 2 microstrip patch antenna array, continuously variable delay lines with a novel geometry, RF feeding, and biasing networks. The expected insertion loss of the variable delay line is less than 4 dB with a maximum differential phase shift of 300°. During the measurements, the antenna is steered by applying an appropriate dc biasing in the range of 0-15 V to the variable delay lines. It is also shown that the return loss is always better than 15 dB at the operating frequency when the antenna is steered.
99 citations
TL;DR: In this paper, dispersion behavior of two specific Vivaldi antennas has been fully investigated in both frequency and time domains and results are verified by experimental data.
Abstract: Besides the return loss and radiation pattern, dispersion characteristic of the antenna is one of the most important factors which should be considered in ultra wideband applications. In this paper, dispersion behavior of two specific Vivaldi antennas has been fully investigated in both frequency and time domains. All simulations are carried out by CST MS software. Moreover, by fabricating the antennas, the simulation results are verified by experimental data.
99 citations
TL;DR: In this paper, a broadband planar Sierpinski fractal antenna for multiband application is proposed, designed, and tested using perturbation of the perturbed fractal patch and slotted ground plane to achieve broadband characteristics.
Abstract: A broadband planar Sierpinski fractal antenna for multiband application is proposed, designed, and tested. The perturbed Sierpinski fractal patch and slotted ground plane are employed to achieve broadband characteristics. The implemented antenna including the ground plane has a total dimension of 100 times 53.7 times 0.8 mm3. The measured 10-dB return loss bandwidths are 808-1008 MHz (22%) and 1581-2760 MHz (54.3%), which cover the GSM/DCS/PCS/IMT-2000/ISM/satellite DMB bands. The measured return loss, radiation patterns, and gain of the proposed antenna are presented and compared with simulated results.
99 citations
Abstract: In this paper, a cylindrical electromagnetic bandgap (CEBG) structure composed of infinite metallic wires is analyzed, designed and used as a model to develop a new reconfigurable directive antenna. This structure is circularly and radially periodic, and it is excited at its center using an omnidirectional source. The analysis is based on calculating the transmission and reflection coefficients of a single cylindrical frequency selective surface (FSS) and then, considering only the fundamental mode interaction, deducing the frequency response of the CEBG structure composed of multiple cylindrical FSSs. For this structure, new analytical formulas are derived, and their accuracy is assessed compared to those obtained by the finite-difference time-domain method. As in rectangularly periodic structure case, the frequency response of the CEBG structure exhibits pass-bands and bandgaps, and it is possible to obtain directive beams by introducing defects in the periodic structure. Using this concept, a new antenna was developed to obtain a controllable directive beam. An antenna prototype, without control, was designed, fabricated, and tested. An excellent agreement was obtained between theory and experiment for both return loss and radiation patterns.
99 citations
Patent•
22 Apr 2009
TL;DR: In this article, a loop antenna is wound about an inner housing of an implantable medical device and capacitively coupled to the loop antenna external to the inner housing to increase efficiency and decrease Return Loss Response of the implantable device.
Abstract: Embodiments of an implantable medical device includes a loop antenna wound about an inner housing. The loop antenna may form a partial winding, a complete winding, or multiple windings about the inner housing. One or more additional antennae may be capacitively coupled to the loop antenna external to the inner housing to increase efficiency and decrease Return Loss Response of the implantable device. The additional antenna may be balanced or unbalanced antennae.
98 citations