Reconfigurable Impedance Matching Network Research Articles

Switchable Filtering Circuit With Single- and Multi-Channel Operations

In this brief, we proposed a switchable filtering circuit with single- and multi-channel operations. It is a six-port circuit, consisting of three sections, namely, a switchable single- and quad-channel filtering circuit, a reconfigurable impedance matching network (IMN), and a single-pole double-throw (SPDT) switch. Two of the ports can be switched to satisfy the requirement of a time division duplexer sub-system, while other four ports can be reconfigured to transmit or receive signals in one channel or four channels. The presented switchable circuit can be utilized as the feeding network of a switchable directive and omni-directional antenna systems by using only directive antennas, while the omni-directional antenna can be eliminated. The design methods and experimental results of the presented switchable filtering circuits are given to verify the proposed ideas.

Reconfigurable Impedance Matching Networks With Controllable Phase Shift

Two kinds of reconfigurable impedance matching networks with controllable phase shift are proposed. The reconfigurable networks can match different loads with desired phase shift at center frequency and no extra phase shifter is needed. The two networks are realized by using varactor diodes and switches, respectively. The design equations and achievable phase shift range of the two networks are derived. Two prototypes working at 1 GHz were fabricated for verification. The measured results show good return loss response and precise phase shift value.

A Wideband Reconfigurable Impedance Matching Network for Complex Loads

A novel wideband reconfigurable impedance matching network is presented, which consists of a main transmission line and several switchable branch lines. The proposed network can match different complex loads at different frequency bands. A novel optimization method is proposed to calculate the circuit parameters efficiently. The calculation results indicate that the proposed impedance matching network can match a broad range of complex loads with wideband operation. For demonstration, two prototypes are designed and fabricated. Good agreement is observed between the measured and expected performances.

Tunable Matching Network Using MEMS Switches

This paper presents a novel approach in order to construct low-loss reconfigurable impedance matching networks and tuners using MEMS series-contact switches and periodic defected-ground-structures (DGSs) implemented on coplanar waveguide (CPW) transmission lines. The application of DGSs results in an improved insertion loss and power handling capability compared to the conventional RF MEMS impedance tuning networks. The proposed structure consists of 12 DGSs and RF MEMS series-contact switches. The tunable matching network was fabricated on a silicon substrate and is only 1.4×̃˾̈˰̽̽˰̹̾˰̵̹̓͊˾˰̸̵̤˰̵̵̴̱̽̓͂ͅ˰̼̿̓̓˰̶̿˰̸̵̈́˰̵͇̻̾̈́̿͂˰̸̵͇̾˰̵̴̓ͅ˰̈́̿˰̸̱̳̽̈́˰̱˰́̀˰Ω˰̴̼̱̿˰̈́̿˰̅̀˰Ω˰̶͂̿m 5GHz up to 40 GHz is only 0.8 dB. The results show that the tuner can achieve a broadband impedance match for a wide variety of loads that are either purely resistive or that have a large reactance as well.

Design Methodology and Optimization of Distributed MEMS Matching Networks for Low-Microwave-Frequency Applications

A design methodology for the distributed microelectromechanical system (MEMS) impedance matching networks based on the optimization of the uniformity of the Smith chart coverage has been developed. The proposed approach was validated through a comparison between a traditional coplanar waveguide (CPW) design and an improved design based on a slow-wave (SW) structure. The enhanced reconfigurable impedance matching network has been developed for low-frequency applications. The network is based on a distributed MEMS transmission line (DMTL) coupled with the SW structure to reduce the total physical length of the network by 25% in comparison with a traditional DMTL. An extensive analysis was performed to identify the impact of each design parameter in order to optimize the structure and reduce the required size for relatively low-frequency applications. Several parameters are extracted from the electromagnetic simulation results and are used to design the proposed impedance matching network. Measurement results confirm the efficiency of the proposed design methodology in improving the impedance coverage and also miniaturization of the DMTL impedance matching networks.