Return loss

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

High-power high-temperature superconducting microstrip filters for cellular base-station applications

Abstract: We report narrowband microstrip filters with low insertion loss and high power-handling capabilities made from YBa/sub 2/Cu/sub 3/O/sub 7/(-x) high-temperature superconducting films. One 5-pole filter on a LaAlO/sub 3/ substrate, consisting of backward-coupled and forward-coupled resonators, can handle over 27 W input power at 10 K. It has 1% fractional bandwidth and 10-/spl Omega/ internal impedance. The insertion loss increase in passband at 10 K, as the input power changed from a few mW to 27 W, is less than 0.25 dB. We also report a forward-coupled microstrip filter centered at 2 GHz, with a 1.2% fractional bandwidth, 10-/spl Omega/ internal impedance, and parallel-coupled feed lines. We applied over 10 /spl Omega/ to the filter at 45 K without noticeable degradation of the filter performance. The insertion loss at 45 K is less than 0.2 dB. The return loss is better than 12 dB. >

Compact UWB Chip Antenna Design Using the Coupling Concept

Abstract: This article describes a compact UWB chip antenna using the coupling concept. The inclined slot is inserted on the rectangular radiating patch of the UWB chip antenna. From experimental results, the measured impedance bandwidth of the antenna (defined by −6 dB return loss) is 2.5GHz (3–5.5 GHz). Also, the proposed antenna exhibits good radiation patterns with small gain variation (2.5–3.5 dBi) in the operating frequency band. Details of the proposed antenna design and the simulated and measured results are presented and discussed.

Compact Integrated Full-Duplex Gap Waveguide-Based Radio Front End For Multi-Gbit/s Point-to-Point Backhaul Links at E-Band

Abstract: This paper presents the design and realization of a high data rate radio front-end module for point-to-point backhaul links at E-band. The design module consists of four vertically stacked unconnected metal layers without any galvanic and electrical contact requirements among the building blocks, by using gap waveguide technology. The module components are a high-gain array antenna, diplexer, and circuitry consisting of a transmitter (Tx) and a receiver (Rx) monolithic microwave integrated circuits (MMICs) on a carrier board, which is successfully integrated into one package with a novel architecture and a compact form. The diplexer consists of two direct-coupled cavity bandpass filters with channels at 71–76 GHz and 81–86 GHz with a measured return loss of 15 dB and an isolation greater than 50 dB. A wideband $16\times 16$ slot array antenna with a measured gain of more than 31 dBi is used to provide high directivity. The measured results show that the packaged transmitter provides a conversion gain of 22 and 20 dB at 76 and 86 GHz, respectively, with an output power of 14 and 16 dBm at 1-dB gain compression point, at the same frequencies. The packaged receiver shows an average conversion gain of 20 dB at 71–76-GHz and 24 dB at 81–86-GHz bands. A real-time wireless data transmission is successfully demonstrated with a data rate of 8 Gbit/s using 32-quadrature amplitude modulated signal over 1.8-GHz channel bandwidth with spectral efficiency of 4.44 bit/s/Hz. The proposed radio front end provides the advantages of low loss, high efficiency, compact integration, and a simple mechanical assembly, which makes it a suitable solution for small-cell backhaul links.

94 GHz Folded Fresnel Reflector Using C-Patch Elements

Abstract: A 94 GHz folded Fresnel reflector (FFR) for helicopter collision avoidance Radar is presented. The antenna system consists of a primary source illuminating a semi-reflecting grid that reflects the primary source polarization toward the main reflector opposite the grid. The main reflector has two functions. It focuses the field in the desired direction and rotates the incident polarization by 90deg to enable it to pass through the grid and radiate. Specific patch elements having a C-shape have been designed for this purpose. In order to increase overall efficiency, the reflector combines 8 correcting zones in its center and 4 at the periphery. The reflector is manufactured using standard photolithographic techniques. The primary source consists of a metal waveguide covered with a small frequency selective surface (FSS) for matching purposes. The maximum measured gain is 36.5 dBi at 94 GHz. The maximum side lobe level is -18 dB. The return loss value does not exceed -25 dB. The frequency bandwidth -3 dB in gain and return loss is 10%. In-flight measurements were conducted demonstrating the ability to detect power lines at distances up to 680 m.

Broadband half-mode substrate integrated waveguide (HMSIW) Wilkinson power divider

Abstract: A broadband H-plane Wilkinson power divider that makes use of the half-mode substrate integrated waveguide (HMSIW) technique is presented in this work for the first time. This broadband power divider utilizes the half-mode structure of SIWs such that the overall size is largely reduced at least by half. In addition, the lossy network or resistor branch is integrated with the SIW structure in order to obtain good output matching and isolation if unbalanced signals are combined or divided. The proposed concept is then validated by theoretical analysis and measurements. Good input return loss (S 11 ) and insertion loss (S 21 , S 31 ) performances are obtained theoretically and experimentally across a very broad bandwidth from 18 GHz up to 40 GHz. In the meanwhile, output return loss (S 22 , S 33 ) and isolation (S 23 ) better than −10 dB are also ensured across a 64% bandwidth from 18 GHz to 35 GHz.