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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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Journal ArticleDOI
TL;DR: In this article, a reconfigurable filtering transmission line (RFTL) with 90° or −90° phase shift was designed and constructed by substituting the basic unit of quarter-wavelength (λ/4$ ) transmission line in the conventional couplers with the proposed RFTL.
Abstract: This paper reports on, for the first time, the design of filtering couplers with reconfigurable frequency. The reconfigurable filtering transmission lines (RFTLs) with 90° or −90° phase shift are first designed, and then the reconfigurable filtering couplers are constructed by substituting the basic unit of quarter-wavelength ( $\lambda/4$ ) transmission line in the conventional couplers with the proposed RFTL. The tunable capacitor loaded half-wavelength ( $\lambda/2$ ) resonators are used to tune the center frequency of RFTL. By properly controlling the electric or magnetic coupling between the resonators, the phase shift of 90° or −90° of the RFTLs can be realized, respectively, while maintaining a near constant bandwidth. The external coupling along with a pair of transmission zeros is achieved by asymmetric tap feeding of the RFTLs. For verification, a class of frequency-reconfigurable filtering couplers is designed and fabricated. First, a reconfigurable filtering rat-race coupler is designed and fabricated. The measured center frequency is tuned from 700 to 1840 MHz while maintaining a 3-dB fractional bandwidth of 13% ± 0.5%/13.7% ± 0.6%, insertion loss of 8.1–6.9/8.3–5.9 dB, return loss of better than 13 dB, and isolation of better than 21 dB. Second, a reconfigurable filtering quadrature coupler is designed and fabricated. The measured center frequency is tuned from 947 to 1775 MHz while maintaining a 1-dB bandwidth of 75 ± 5/65 ± 10 MHz, insertion loss of 8.3–6.9/8.3–7.1 dB, return loss of better than 14 dB, and isolation of better than 14 dB.

28 citations

Journal ArticleDOI
TL;DR: In this article, a planar microstrip filter with a notched band is introduced, which employs a split-ring resonator defected ground structure (DSRR) to reject the undesired wireless local-area network (WLAN) radio signals.
Abstract: A topology of a compact planar microstrip filter with a notched band is introduced, which employs a split-ring resonator defected ground structure (DSRR). Folded short-circuited stubs are used to realise the bandpass filter with good selectivity and out-of-band characteristics. By employing a split-ring resonator defected ground structure, a narrow notched band was introduced to reject the undesired wireless local-area network (WLAN) radio signals. The measured insertion loss is less than 1.6 dB, the return loss is more than 13 dB, and the variation of group delay is less than 0.5 ns throughout most of the two passbands. The width of the narrow notched band is about 1 GHz and the attenuation is more than 25 dB at the centre frequency of 5.4 GHz.

28 citations

Proceedings ArticleDOI
15 Nov 2011
TL;DR: A novel Koch-meander Fractal antenna has been proposed for the application of WLAN USB dongle and is capable of covering the whole band required for the WLAN 802.11 a/b/g standards.
Abstract: There is a current upsurge for the high data rate and wide bandwidth in the communication technologies. This has posed several challenges for the researchers. These challenges include but are not limited to size reduction, high efficiency, and low-cost. The prevailing fashion in the communication system is to integrate several WLAN standards in small user equipment. The emergence of the USB dongle for WLAN has attracted the antenna design engineers to design multi band antennas. The antenna size is restricted to the small size of the USB dongle. The main challenge is to reduce the antenna size without compromising on the performance related characteristics such as; wide bandwidth, low VSWR, high gain and high radiation efficiency. In this paper a novel Koch-meander Fractal antenna has been proposed for the application of WLAN USB dongle. The proposed compact antenna is simulated in CST microwave studio. The simulation results depicts that the antenna has a −10 dB return loss bandwidth of 2.2909–2.553 GHz and 5.1406–5.8737 GHz. The minimum return loss of −28.9 dB is achieved at the lower band of 2.41 GHz. While the upper band depicts a return loss of −20.8 dB at 5.36 GHz. The proposed antenna is capable of covering the whole band required for the WLAN 802.11 a/b/g standards.

28 citations

Journal ArticleDOI
TL;DR: In this paper, a singlemode fiber optical switch is described that interposes a gold-coated silicon vane in a fiber gap to achieve 0.81 dB minimum insertion loss in the transmit state with 38-80 dB transmission isolation and a 2.15 dB return loss.
Abstract: A new MEMS (micro electromechanical system) singlemode fibre optical switch is described that interposes a gold-coated silicon vane in a fibre gap to achieve 0.81 dB minimum insertion loss in the transmit state with 38-80 dB transmission isolation and a 2.15 dB return loss in the reflection state, all in the 1550 nm wavelength region. Control voltages were in the range 5-40 V and a switching time of 64 /spl mu/s was achieved.

28 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023285
2022837
2021601
2020738
2019970
2018994