Return loss

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

A compact CMOS Marchand balun incorporating meandered multilayer edge-coupled transmission lines

Abstract: This work presents a compact CMOS Marchand balun design, which consists of the meandered two-conductor edge-coupled complementary-conducting-strip coupled-line (CCS CL). The CCS CL, which is fully compatible with the standard CMOS process, provides various structural parameters to synthesize the desired coupling coefficient for Marchand balun realization. The prototype, which is fabricated by the standard 0.18-µm 1P6M CMOS technology, reveals circuit size of 240.0 µm × 240.0 µm (without contact pads). The measured results, which are collected based on 50-Ω system, demonstrate excellent agreements with those of the simulations. The input return loss is less than −15.0 dB from 21.6 GHz to 33.1 GHz. The measured insertion losses between input and two output ports (S 21 and S 31 ) are 5.90 dB and 4.38 dB at 23.6 GHz, respectively. The phase difference between two output ports is 180° ± 10° from 15.5 GHz to 40.0 GHz.

CPW-fed ultra wideband (UWB) monopoles with band rejection characteristic on ultra thin organic substrate

Abstract: Two CPW-fed compact elliptical monopole UWB antennas are introduced with band rejection characteristic at the band used for wireless LAN applications. The antennas are fabricated on ultra thin (100 mum) liquid crystal polymer (LCP) and the band notch is caused by the presence of a resonating slot within the elliptical radiator. The two investigated antennas have a U-shaped slot and a C-shaped slot respectively. From the presented return loss and VSWR measurements, the C-shaped slot causes a wider rejection band compared to the U-shaped slot that could be used for the design of UWB antennas with reconfigurable sub bands. Both designs present almost identical radiation pattern behavior with the design without any slot with the exemption of the gain in the frequency notch band, which is maintained negative.

E-plane directional couplers in substrate-integrated waveguide technology

Abstract: In order to analyze and design components in substrate-integrated waveguide technology, it is important that the transitions to interface ports do not significantly influence the component's performance. In this paper, it is demonstrated that the commonly used microstrip-to-SIW transitions are not sufficient to evaluate a SIW structure within a SIW environment. Therefore, we present all-dielectric rectangular waveguide interface ports that considerably reduce the reflections at the transition to the SIW component. These new ports are then applied to the design of SIW E-plane couplers, both with standard dual-circular apertures and as Riblet-Saad couplers. It is demonstrated that SIW couplers with return loss and isolation of much better than 20 dB can be designed. Several 10 db and 3 dB couplers covering the entire Ka-band frequency range are presented. The basic design procedure is validated by comparison with measurements and computations available in the common literature.

Return loss requirements for optical duplex transmission

Abstract: There has recently been considerable attention given to bidirectional transmission over the same optical fiber. One of the impairments associated with this type of system is receiver sensitivity degradation due to reflected power. This paper presents an analysis of this impairment and compares it with experimental results. It is shown that for a certain class of systems relatively large reflections can be tolerated for a small sacrifice in system range.

Design of 3.1---12 GHz Printed Elliptical Disc Monopole Antenna with Half Circular Modified Ground Plane for UWB Application

Abstract: This paper presents a new design of an elliptical disc monopole antenna for ultra wideband (UWB) applications. The antenna is fed by a 50 ? microstrip line and printed on a dielectric FR4 substrate of permittivity ? r = 4.7 and height h = 1.6 mm. The optimization on the planar elliptical disc monopole has been presented to accomplish an ultra wide 10 dB return loss bandwidth. The design includes a half-modified circular ground plane with two short I-shaped sleeves in the middle to enhance the S-parameter characteristics across the whole UWB frequency band. Furthermore, compared to a simple rectangular shaped ground plane, the proposed design enhances the bandwidth and improves input return loss. The obtained results confirm that the proposed antenna achieves greater than 90 % radiation efficiency, better than 10 dB return loss, and 0.1 ns group delay in the frequency range of 3.1---12 GHz. The parameters, which affect the performance of the antenna with respect to frequency domain and time domain characteristics, are investigated also. In addition, the proposed antenna is fabricated and the simulation results are compared to the measurement results to prove the superiority of the antenna.