Return loss

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

Low-Cost Broadband Circularly Polarized Printed Antennas and Array

Abstract: This paper presents the design, simulation, and measurements of two low-cost broadband circularly polarized (CP) printed antennas: an element and an array at 2 GHz. To realize the broadband circularly polarized antenna element, a circular microstrip patch is electromagnetically coupled by crossed slots cut in the ground plane, which is fed by an L-shaped microstrip feed. Two orthogonal modes in the patch are excited by using the crossed slots, and a single L-shaped feed provides a 90deg phase shift between two orthogonal slots. The antenna element achieves a 9.6% bandwidth for an axial ratio (AR) below 3 dB and a voltage standing wave ratio (VSWR) below 1.5. To further improve the performance, a sequentially rotated feed network is designed for a 2 times 2 array. The axial ratio value of the array is below 3 dB within a 27.2% bandwidth, from 1.75 GHz to 2.3 GHz. The return loss is above 10 dB within a 41% bandwidth, from 1.62 GHz to 2.45 GHz. Details of the proposed antenna element and the array design are described, and both the simulation and the experimental results are presented and discussed.

Binary-Coded 4.25-bit $W$ -Band Monocrystalline–Silicon MEMS Multistage Dielectric-Block Phase Shifters

Abstract: This paper presents a novel concept of a microwave microelectromechanical systems (MEMS) reconfigurable dielectric-block phase shifter with best loss/bit at the nominal frequency and best maximum return and insertion loss ever reported over the whole W-band A seven-stage phase shifter is constructed by lambda/2-long high-resistivity silicon dielectric blocks, which can be moved vertically by MEMS electrostatic actuators based on highly reliable monocrystalline silicon flexures on-top of a 3-D micromachined coplanar transmission line The dielectric constant of each block is artificially tailor made by etching a periodic pattern into the structure Stages of 15deg, 30deg, and 45deg are optimized for 75 GHz and put into a binary-coded 15deg + 30deg + 5 times 45deg configuration with a total phase shift of 270deg in 19 times 15deg steps (425 bits) Return and insertion losses are better than -17 and -35 dB at 75 GHz, corresponding to a loss of -082 dB/bit, and a phase shift efficiency of 711deg/dB and 49002deg/cm Return and insertion losses are better than -12 and -4 dB for any phase combination up to 110 GHz (983deg/dB; 7156deg/cm) The intercept point of third order, determined by nonlinearity measurements and intermodulation analysis, is 4915 dBm for input power modulation from 10 to 40 dBm The power handling is only limited by the transmission line itself since no current-limiting thin air-suspended metallic bridges as in conventional MEMS phase shifters are utilized This is confirmed by temperature measurements at 40 dBm at 3 GHz with skin effect adjusted extrapolation to 75 GHz by electrothermal finite-element method simulations

Miniature Long-Term Evolution (LTE) MIMO Ferrite Antenna

Abstract: A long-term evolution (LTE) MIMO ferrite antenna was fabricated on Ni0.5Mn0.2Co0.07Fe2.23O4 ferrite substrate (14 × 7 × 3 mm3) and characterized for antenna performance. Measured return loss and isolation were -26 and -16.4 dB at 720 MHz, respectively. Correlation coefficient calculated from experimental S-parameters (S11, S22, S12, and S21) was less than 0.02 in the LTE band. Three-dimensional peak gain at 746 MHz was measured to be -8.83 dBi for antenna 1 and -8.32 dBi for antenna 2. These low antenna gains are attributed to high magnetic loss of ferrite substrate. Performance simulation suggests that antenna gain can be further improved up to -3.14 dBi with the use of low-loss ferrite.

A Novel Dual-Band (38/60 GHz) Patch Antenna for 5G Mobile Handsets

Abstract: A compact dual-frequency ( 38 / 60 GHz ) microstrip patch antenna with novel design is proposed for 5G mobile handsets to combine complicated radiation mechanisms for dual-band operation. The proposed antenna is composed of two electromagnetically coupled patches. The first patch is directly fed by a microstrip line and is mainly responsible for radiation in the lower band ( 38 GHz ). The second patch is fed through both capacitive and inductive coupling to the first patch and is mainly responsible for radiation in the upper frequency band ( 60 GHz ). Numerical and experimental results show good performance regarding return loss, bandwidth, radiation patterns, radiation efficiency, and gain. The impedance matching bandwidths achieved in the 38 GHz and 60 GHz bands are about 2 GHz and 3.2 GHz , respectively. The minimum value of the return loss is − 42 dB for the 38 GHz band and − 47 for the 60 GHz band. Radiation patterns are omnidirectional with a balloon-like shape for both bands, which makes the proposed single antenna an excellent candidate for a multiple-input multiple-output (MIMO) system constructed from a number of properly allocated elements for 5G mobile communications with excellent diversity schemes. Numerical comparisons show that the proposed antenna is superior to other published designs.

Design of an LTCC switch diplexer front-end module for GSM/DCS/PCS applications

Abstract: This paper presents the results of an antenna switch/filter module integrating GSM/DCS/PCS diplexer functions and Rx/Tx antenna switching on a low temperature co-fired ceramic (LTCC) substrate. Although the RF front-end module (FEM) was configured for dual-band (GSM/DCS) applications, the high pass filter function was designed to operate in the PCS band as well. Harmonic filtering was included in the diplexer design, which reduced the filtering requirements for the power amplifier. The 50-ohm in/out FEM utilized GaAs PHEMT switches and associated bias passives surface mounted on the LTCC substrate. S-parameter characterization of the FEM demonstrated excellent insertion and return loss characteristics. For GSM, the return and insertion losses measured at 912 MHz were better than 28 dB and less than 1.7 dB, respectively. Similarly, for DCS applications, the return and insertion losses at 1.77 GHz were better than 19 dB and less than 1.5 dB, respectively. In both cases, the design approach yielded excellent agreement between measured and simulated results.