Mechanical Tuning of Substrate Integrated Waveguide Filters

Abstract

Abstract-This paper presents a novel approach for tuning substrate integrated waveguide (SIW) resonators, realized by placing an additional metalized via-hole on the waveguide cavity. The approach presented here can be applied as a trimming technique, as well as to develop filter designs with tunable center frequencies and tunable bandwidths. Three different filters are designed and implemented, demonstrating excellent trimming, 10% tuning of the center frequency, and 100% tuning of the bandwidth respectively.

Dual-Band Dual-Mode Substrate Integrated Waveguide Filters with Independently Reconfigurable TE101 Resonant Mode

“…Recently, a number of multi-band and tunable/reconfigurable filters have been reported in the literatures including coplanar waveguide filters 1 , microstrip filters 2 , and substrate integrated waveguide (SIW) filters 3 . Due to the advantages such as easy fabrication, simple integration with active devices, compact size, low cost, mass-production, small loss, higher quality factor, high-skirt filtering selectivity, complete shielding, and enhanced power capability of the SIW technology, novel SIW-based multi-band 3 4 5 or tunable/reconfigurable filters 6 7 8 9 10 11 have received particular attention. In general, compared with SIW-based multi-band filters, which possess low losses, mass production, high quality factor, and high power capacity, SIW-based tunable/reconfigurable filters, which use a single dielectric to merge waveguide cavities with planar structures, can selectively cover multiple frequency bands while maintaining lower crosstalk sensitivity.…”

“…There are only two categories of SIW-based tunable/reconfigurable filters: 1) the electrically tunable filters 6 7 8 , and 2) the mechanically tunable ones 9 10 11 12 . By applying controllable DC voltages at each varactor on complementary split-ring resonators, the pass-band tuning performance can be achieved for these SIW-based electrically tunable filters 6 7 8 .…”

“…By applying controllable DC voltages at each varactor on complementary split-ring resonators, the pass-band tuning performance can be achieved for these SIW-based electrically tunable filters 6 7 8 . For mechanically tunable filters 9 10 11 12 , the chosen switching elements directly connect the additional metallized via hole with the top metalized layer on the cavity, which can be used as trimming technique and to develop tunable filters. Their operating-frequency adjustability is achieved by discretely controlling the switch states.…”

Substrate Integrated Coaxial Filters with Fixed and Tunable Responses

“…Preliminary works on reconfigurable structure in this technology have been published in 2005, but it is only from 2009 that the research activity increases resulting in many publications. In this context, many types of tuning elements have been used for implementing the reconfigurable filters in SIW, and among them, there are piezoelectric actuators [62], tuning screws [63,64], varactor diodes [65][66][67], PIN diodes [68], RF MEMS switches [69] and ferrite slabs [70,71].…”

“…Measured results exhibit a tuning range of 8%, where the resonant frequency varies from 6.85 to 7.42 GHz, with a measured Q u of 94. Following this approach, the design of SIW filters with tunable centre frequency and tunable bandwidth have been implemented by the same authors in [64]. Three different filters are designed and implemented, demonstrating 10% tuning of the center frequency, and 100% tuning of the filter bandwidth.…”