A 1.2–1.6-GHz Substrate-Integrated-Waveguide RF MEMS Tunable Filter

Abstract

This paper presents a high-performance substrate-integrated-waveguide RF microelectromechanical systems (MEMS) tunable filter for 1.2-1.6-GHz frequency range. The proposed filter is developed using packaged RF MEMS switches and utilizes a two-layer structure that effectively isolates the cavity filter from the RF MEMS switch circuitry. The two-pole filter implemented on RT/Duroid 6010LM exhibits an insertion loss of 2.2-4.1 dB and a return loss better than 15 dB for all tuning states. The relative bandwidth of the filter is 3.7 ± 0.5% over the tuning range. The measuredQuof the filter is 93-132 over the tuning range, which is the best reportedQin filters using off-the-shelf RF MEMS switches on conventional printed circuit board substrates. In addition, an upper stopband rejection better than 28 dB is obtained up to 4.0 GHz by employing low-pass filters at the bandpass filter terminals at the cost of 0.7-1.0-dB increase in the insertion loss.

Theory and Design of Octave Tunable Filters With Lumped Tuning Elements

“…surface mount tuning components as an alternative medium between low Q u planer structures and high Q u 3-D cavities. In [9], packaged RF-MEMS switches mounted on a substrate integrated waveguide (SIW) are used to get Q u of 132-93 at 1.6-1.2 GHz. However the tuning range is limited to a few states.…”

Integrable microwave filter based on a photonic crystal delay line

“…An important example is microwave signal filtering, which is ubiquitous in communications, radio-over-fibre, radar, radio astronomy and digital satellite communication systems 5 . Agility, reconfiguratibily and tunability are highly desirable features, which are, however, not straightforward to implement using traditional electronic circuitry, for example, microstrip 6 or coplanar waveguide lines 7 , substrate-integrated waveguides 8 and superconducting circuits 9 . To this end, approaches based on ferroelectric materials are being investigated, such as barium strontium titanate 10 , semiconductor varactors diodes 6 , metamaterials 7 , micro-electro-mechanical systems 8 and SiGe BiCMOS-compatible structures 11 .…”

Developing One-Dimensional Electronically Tunable Microwave and Millimeter-Wave Components and Devices Towards Two-Dimensional Electromagnetically Reconfigurable Platform

“…Hence, MEMS schemes have attracted much attention, which present a very promising scheme in realizing a wide range of RF and microwave tunable components and devices. In the literature, many types of tunable devices based on MEMS technology can be found, including phase shifters [20,21], antennas [22] and filters [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. In this paper, a short overview regarding the current status of MEMS based tunable filters is presented.…”

“…It is a good example in which MEMS switches are used in controlling resonant frequency, input/output couplings, and couplings between resonators to achieve a fully-reconfigurable Figure 6. Fabricated tunable SIW-based low-frequency band-pass filter using direct contact MEMS switches [27].…”

“…A new type of tunable filter based on substrate integrated waveguide (SIW) technology was presented in [27]. As illustrated in Figure 6, the filter topology consists of two SIW cavities that are coupled to each other via an iris window.…”