Return loss

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

Broadband composite right/left-handed coplanar waveguide power splitters with arbitrary phase responses and balun and antenna applications

Abstract: This study presents novel coplanar waveguide (CPW) power splitters comprising a CPW T-junction with outputs attached to phase-adjusting circuits, i.e., the composite right/left-handed (CRLH) CPW and the conventional CPW, to achieve a constant phase difference with arbitrary value over a wide bandwidth. To demonstrate the proposed technique, a 180/spl deg/ CRLH CPW power splitter with a phase error of less than 10/spl deg/ and a magnitude difference of below 1.5 dB within 2.4 to 5.22 GHz is experimentally demonstrated. Compared with the conventional 180/spl deg/ delay-line power splitter, the proposed structure possesses not only superior phase and magnitude performances but also a 37% size reduction. The equivalent circuit of the CRLH CPW, which represents the left-handed (LH), right-handed (RH), and lossy characteristics, is constructed and the results obtained are in good agreement with the full-wave simulation and measurement. Applications involving the wideband coplanar waveguide-to-coplanar stripline (CPW-to-CPS) transition and the tapered loop antenna are presented to stress the practicality of the 180/spl deg/ CRLH CPW power splitter. The 3-dB insertion loss bandwidth is measured as 98% for the case of a back-to-back CPW-to-CPS transition. The tapered loop antenna fed by the proposed transition achieves a measured 10-dB return loss bandwidth of 114%, and shows similar radiation patterns and 6-9 dBi antenna gain in its operating band.

Microstrip Patch Antenna Bandwidth Enhancement Using AMC/EBG Structures

Abstract: A microstrip patch antenna with bandwidth enhancement by means of artificial magnetic conductor (AMC)/electromagnetic band-gap structure (EGB) is presented The electrical characteristics of the embedded structure are evaluated using MoM simulations The manufactured prototypes are characterized in terms of return loss, gain, and radiation pattern measurements in an anechoic chamber

Dielectric constant and loss tangent measurement using a stripline fixture

Abstract: A new approach to dielectric material characterization with a vector network analyzer is presented. As the characteristic impedance (Z/sub 0/) of a stripline transmission line can be accurately determined by measuring the two-port scattering parameters in the frequency range of interest, the dielectric constant of the insulation material that consists as part of the stripline configuration is then obtained by a relationship to the characteristic impedance. The dielectric loss (or loss tangent) can be determined by measuring the return loss and the insertion loss of the stripline. The validity of the technique is demonstrated for well-characterized dielectric materials such as Teflon-based and other composite laminates. The technique is then applied to integrated circuit (IC) molding compounds as-processed.

Substrate integrated waveguide (SIW) broadband compensating phase shifter

Abstract: In this paper, a broadband compensating phase shifter is presented based on the substrate integrated waveguide (SIW) technology. The SIW is a dispersive guided-wave structure, but the phase shifts generated by two different structures (the delay line and the equal-length unequal-width phase shifter) have just reverse varying tendencies versus frequency. Thus, the complementing combination of them will make phase shift almost constant over a wide band. Detailed design equations are given following a mathematical analysis. The limitation of variation of SIW width and the tolerance issue are investigated as well. As an example, a 90° compensating phase shifter is designed on a single-layer substrate with normal PCB process at the center frequency of 30 GHz. The amplitude imbalance between the two paths is within 0.2 dB while the phase error is less than 2.5° over the frequency band from 25.1125 to 39.75 GHz, or around 49% relative bandwidth. The return loss is found to be better than 12 dB over the whole frequency band. Measured and simulated results of the proposed structure are in a good agreement. This type of SIW phase shifter is superior to all of its counterparts and increases the relative bandwidth of early designs about five times.

dc electric field tunable bulk acoustic wave solidly mounted resonator using SrTiO3

Abstract: A tunable SrTiO3 solidly mounted bulk acoustic wave resonator has been designed, fabricated, and tested. The solidly mounted resonator was implemented using an acoustical Bragg reflector of alternating high and low acoustic impedance layers. The resonator demonstrated a frequency tunability of 1%, from 5.87to5.81GHz with an applied bias of 0–7.5V, respectively. A return loss of −6.5dB was observed at an applied bias of 7.5V. The quality factor at the resonant frequency was 78 and relatively constant with applied bias. The effective electromechanical coupling coefficient was 2% and near linear with applied bias.