This paper presents the design, fabrication, and measurement of a double-slug tunable matching network based on a distributed microelectromechanical-system (MEMS) transmission line. The tuner is implemented with a new minimal-contact RF-MEMS varactor that largely eliminates stiction while allowing the capacitance ratio to be set anywhere from 2 to 5. The measured performance of the tunable matching network demonstrates complete coverage of the Smith chart out to a maximum voltage standing-wave ratio of 12:1 from 10 to 30 GHz with excellent agreement between measurement and simulation results.

Distributed MEMS tunable matching network using minimal-contact RF-MEMS varactors

This paper presents the design, fabrication, and characterization of a compact narrowband tunable impedance-matching network. A prototype was fabricated in hybrid technology using coplanar waveguide transmission lines and surface-mounted components. The network consists of a II-structure with tunable components made of varactors in series with inductors. Simulations and measurements are in good agreement. A new measurement methodology suitable for tunable impedance-matching networks is proposed. The results show that complex impedances with magnitudes varying from 6 Omega to 1 kOmega can be matched at 1 GHz and tuned in a 50% bandwidth. In addition, nonlinear measurements were done to fully characterize the network. The 1-dB compression point is reached at an input power of 20 dBm, while the input power for the third-order intermodulation intercept point is 21.3 dBm for a 1-kHz offset between the two input frequencies.

Complete Design and Measurement Methodology for a Tunable RF Impedance-Matching Network

Impedance matching network for high frequency ultrasonic transducer for cellular applications

A compact continuously varactor-tuned low-pass filter using microstrip stepped-impedance hairpin resonators is proposed in this paper. A detailed theoretical analysis for the performance tuning mechanism is illustrated by using equivalent circuit models. The experiment results are provided to validate the proposed filter. From the measured results, it is found that five varactor diodes with two applied bias voltages used in the proposed design work well as a flexible tuning network, which not only provide a wide frequency tuning range of 46% from 1.60 to 2.94 GHz, but also offer an ability of selectivity controlling by using different applied voltages. Furthermore, the proposed filter using multiple cascaded hairpin resonators provides a very sharp cutoff frequency response with low insertion loss in each state, together with a wide and deep stopband with a rejection level greater than 20 dB. Good agreement between the measured and simulated results can be observed finally.

Compact Continuously Tunable Microstrip Low-Pass Filter

Among many microstrip configurations, the open-circuited shunt stub is probably the most common and versatile one. It is capable of performing a wide range of functions. Despite extensive studies and applications of the open-circuited shunt stub, comparatively little is known about aperiodic stubs on a microstrip line. In this paper, aperiodic stubs on a microstrip line are exploited to implement a high-performance low-pass filter and a joint design of the artificial transmission line and low-pass filter. The experimental results validate the performance of the proposed circuits. For the low-pass filter application, the proposed circuit outperforms a seventh-order Butterworth filter while their circuit sizes are comparable. For the joint design, it may potentially enhance the degree of integration in RF and microwave systems.

Design of Artificial Transmission Line and Low-Pass Filter Based on Aperiodic Stubs on a Microstrip Line

This paper describes a new low-pass filter topology based on tapered periodic structures. These filters exhibit interesting characteristics in terms of compactness, return loss, insertion loss, selectivity, and the suppression of spurious frequency bands. Hybrid prototypes with a 1-GHz cutoff frequency, based on a coplanar-waveguide technology, and using both low-cost and high-performance substrates, have been fabricated and measured. Spurious frequency bands can be suppressed to below -22 dB at frequencies up to 20 GHz. Passband ripples are negligible, and the return loss is better than 20 dB. A two-section filter has a length of 0.2 lambda and exhibits a -120-dB/dec selectivity, while a six-section filter is 0.51 lambda long and has a -560-dB/dec selectivity. A design procedure has been established. These filters are compatible with monolithic microwave integrated circuit technologies in which the capacitors can be realized as metal-insulator-metal structures

A compact and selective low-pass filter with reduced spurious responses, based on CPW tapered periodic structures

This paper presents the design, fabrication, and measurement of a compact narrow band impedance matching network with hybrid technology: coplanar waveguide transmission lines and surface mounted components. The device is a Pi-structure with tunable components made of varactors in series with inductors. Simulations and measurements are in good agreement. Results are arrived at by two measurement methods. They show that complex impedances with magnitudes varying from 6Omega to 1 kOmega can be matched at 1 GHz, with a 50% bandwidth.

A RF tunable impedance matching network with a complete design and measurement methodology

The design and measurement of a compact narrowband impedance matching network is presented. The device has been realised in hybrid technology: coplanar waveguide transmission lines and surface-mounted components. The experimental results were carried out through two different measurement methods, a traditional approach and a new faster, simpler one giving the same results. They show that complex impedances with magnitudes varying from 6.3 to 1120 Ω can be matched with a 50% bandwidth around the centre frequency.

Accurate measurement method for characterisation of RF impedance tuners

In this paper, a miniaturized UWB bandpass filter using a hybrid lumped capacitors-distributed transmission lines topology is designed. The filter design rules are carried out and a filter is optimized for a 3 dB fractional bandwidth of 127 % with criteria of compacity, matching and selectivity. A sensitivity study versus critical parameters is also given. The filter length is reduced to 0.18lambda @ 6.5 GHz in comparison with 0.54lambda for the distributed topology. The selectivity is improved with a shape factor equal to 1.28:1 instead of 1.46:1

J.-D. Arnould

Papers

A compact and selective low-pass filter with reduced spurious responses, based on CPW tapered periodic structures

A RF tunable impedance matching network with a complete design and measurement methodology

Accurate measurement method for characterisation of RF impedance tuners

Design of a miniaturized ultra wideband bandpass filter based on a hybrid lumped capacitors - distributed transmission lines topology

"Spurious Supression Semi-lumped UWB Bandpass Filter