Topic
Return loss
About: Return loss is a research topic. Over the lifetime, 11090 publications have been published within this topic receiving 97603 citations.
Papers published on a yearly basis
Papers
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TL;DR: 3D integrated microstrip antenna was designed and fabricated and agrees well with the simulation results, indicating that 3DIMA can be an effective approach for a CLAS.
73 citations
TL;DR: In this article, the authors proposed a distributed digital phase shifters, where both the phase-error bandwidth and the return-loss bandwidth are considered simultaneously, and a complete 4-bit phase shifter with single-pole double-throw switches is then designed and measured.
Abstract: This paper presents the theory and a design method for distributed digital phase shifters, where both the phase-error bandwidth and the return-loss bandwidth are considered simultaneously. The proposed topology of each phase bit consists of a transmission-line (TL) branch and a bandpass filter (BPF) branch. The BPF branch uses grounded shunt λ/4 stubs to achieve phase alignment with the insertion phase of the TL branch. By increasing the number of transmission poles of the BPF branch, the return-loss bandwidth can be increased. Analysis of the BPF topology with one, two, and three transmission poles is provided. The design parameters for 22.5° , 45° , 90° , and 180° are provided for bandwidths of 30%, 50%, 67%, and 100%. The relations between phase error, return loss, and maximum achievable phase shift are shown for the three topologies for design purposes. The methodology is also applicable to bandwidths larger than 100%. To validate the method, four separate L-band phase bits (1-2 GHz) are designed and measured. A complete 4-bit phase shifter with single-pole double-throw switches is then designed and measured. The measured rms phase error of the phase shifter is less than 3.6 °, while the return loss is larger than 15 dB from 1.06 to 1.95 GHz for all 16 phase states.
73 citations
TL;DR: A power divider with ultra-wideband (UWB) performance has been designed and two additional resistors are added along the tapered line to improve the output return loss and isolation.
Abstract: A power divider with ultra-wideband (UWB) performance has been designed. The quarter-wave transformer in the conventional Wilkinson power divider is replaced by an exponentially tapered microstrip line. Since the tapered line provides a consistent impedance transformation across all frequencies, very low amplitude ripple of 0.2dB peak-to-peak in the transmission coe-cient and superior input return loss better than 15dB are achieved over an ultra-wide bandwidth. Two additional resistors are added along the tapered line to improve the output return loss and isolation. Simulation performed using CST Microwave Studio and measured results conflrm the good performance of the proposed circuit. The return loss and the isolation between the output ports are better than 15dB across the band 2{ 10.2GHz. Standard ofi-the-shelf resistance values can be selected by optimizing the physical locations to mount the resistors. Better performance can be achieved with more isolation resistors added. Hence, the number of isolation resistors to be used may be selected based on the desired bandwidth and level of isolation and return loss speciflcations.
73 citations
TL;DR: The proposed antenna uses only one simple filter element to create and control dual notched bands, which give it advantages over the recently proposed band-notch antennas, which make it a suitable candidate for UWB applications.
Abstract: A microstrip line-fed planar antenna with dual notched bands is designed and prototyped for ultrawideband (UWB) communication applications. The dual band-notch characteristic is achieved by etching a single tri-arm resonator below the patch. The simulated and experimental results show that the designed antenna has achieved a wide bandwidth (return loss ≤ -10 dB) ranging from 2.98 to 10.76 GHz with two notched bands operating at 3.5 and 5.5 GHz. The proposed antenna uses only one simple filter element to create and control dual notched bands, which give it advantages over the recently proposed band-notch antennas. In addition, the designed antenna achieved a good gain and exhibits omnidirectional radiation patterns except at notched bands, which make it a suitable candidate for UWB applications.
73 citations
TL;DR: In this article, the design of a simple UHF (ultra-high frequency) RFID (radio frequency identification) reader antenna that operates within the 900 MHz band (902-928 MHz) is studied.
Abstract: The design of a simple UHF (ultrahigh frequency) RFID (radio frequency identification) reader antenna that operates within the 900 MHz band (902-928 MHz) is studied. To generate circular polarization (CP) radiation, a novel method of loading a semicircular slot into the main circular radiating patch is proposed. To allow optimum impedance matching with enhanced CP bandwidth, the L-shaped probe-feed technique is employed in this design. From the experimental results, besides achieving a gain level of more than 7 dBic, the proposed antenna can also yield an impedance bandwidth (10-dB return loss) from 880 to 1100 MHz, while good CP performances between 901 to 930 MHz are exhibited. To further validate the experimental results, parametric studies are also carried out via simulation.
72 citations