Return loss

About: Return loss is a research topic. Over the lifetime, 11090 publications have been published within this topic receiving 97603 citations.

Improved patch antenna performance by using photonic bandgap substrates

Abstract: In this letter, a patch antenna on a photonic bandgap substrate is presented. A reduction in the leel of surface-wae mode excitation has been obtained. This leads to improed efficiency, gain, and far-field radiation pattern. Furthermore, improements in the input return loss hae been reported. Q 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 213)215, 2000.

Compact Wideband Circularly Polarized Patch Antenna for CNSS Applications

Abstract: A compact wideband circularly polarized (CP) patch antenna utilizing a quad-feed network (QFN) and quadruple semi-fan-annulus (QSFA) patches is proposed. For using a coupled-line dual-band power divider (PD) and improved phase shifter (PS) with stepped-impedance-open-stub (SIOS), the QFN has a compact size and exhibits the electromagnetic (EM) simulated bandwidth over 96% for the power distribution -6.5±0.5 dB, return loss (RL) > 14 dB, and a consistent 90° (±9°) phase deviation. Moreover, the QSFA patches can expand the CP bandwidth and reduce the size of the antenna effectively. Measurement results show that the proposed antenna achieves CP bandwidth of 72% from 1.15 to 2.45 GHz for RL > 10 dB, axial ratio dB, and 3-dB gain variation (gain > 4.4 dBi). Therefore, the proposed antenna is a good candidate for Compass Navigation Satellite System (CNSS) applications.

Dual-Band Frequency-Reconfigurable Folded Slot Antenna for Wireless Communications

Abstract: This letter presents a novel frequency-reconfigurable folded slot antenna that could operate in two modes. Both modes have two resonant frequencies. The first mode resonant frequencies are at 3.4 and 5.27 GHz, and it can be used in WLAN band (5.15-5.35 GHz) and WiMAX band (3.40-3.69 GHz). The second mode operating frequencies are at 2.42 and 5.79 GHz, and they can be used in WLAN band (5.725-5.875 GHz) and Bluetooth band (2.40-2.484 GHz). The simulated results both for the return loss and peak gain agree with the measurements. Both the slot and arms of the proposed folded slot antenna are used to result in a resonant frequency, respectively. The advantage of this design is that the antenna is easy to fabricate, and this antenna could work without a complex bias network and a dc blocking capacitor.

Ultra wideband inphase power divider for multilayer technology

Abstract: A multilayer inphase power divider with an ultra wideband behaviour is presented. The proposed divider exploits broadside coupling via a multilayer microstrip/slot configuration. The design method utilised for the device is based on the conformal mapping techniques. The developed device has a compact size with an overall dimension of 20 mm times 30 mm. The simulated and measured results show that the proposed device has equal power division between the two output ports with <0.2 dB amplitude imbalance between them, better than 10 dB return loss and isolation and <2deg phase difference between the two output signals across the frequency band 3.1-10.6 GHz.

Robust Broadband (4 GHz - 16 GHz) GaN MMIC LNA

Abstract: We report robust GaN MMIC LNA operating over 4 GHz-6 GHz frequency range. An FET biased in common-drain configuration is used on the second stage of the MMIC to obtain good input return loss at the optimum noise match over the entire frequency range. The measured noise figure of the MMIC is less than 2 dB over the 4.5 GHz to 16 GHz frequency range and NF has a minimum of 1.45 dB at a frequency of 6.5 GHz. The MMIC gain is more than 10 dB and the input return loss of the MMIC is less than -10 dB over the 4 GHz-15 GHz frequency range. Reported MMIC can survive 5.4 W of incident RF power without front end protection. To the authors knowledge this is the best combination of the noise figure, input return loss, RF survivability and broadband response reported to date in this frequency range using GaN technology. The noise figure of the reported GaN MMIC is 0.5 dB lower than the overall noise figure of an equivalent GaAs pHEMT module consisting of the state of the art LNA and a 5 Watt power limiter at the front end.