Ultra-Wideband Bandpass Filters Using Multilayer Slot Coupled Transitions

Abstract

New Ultra-Wideband (UWB) bandpass filters are proposed and tested. The filters are composed of two microstrip -Conductor-Backed Co-Planar Waveguide (CBCPW) transitions and a multiple-mode resonator, constituted by a line section. The both cases, where the line section is a microstrip or a CBCPW are tested. First, simulated and experimental results for the transition are presented, showing that a wide operating band is obtained. Then, the results for the proposed filters that use this transition structure are presented. Simulated and measured data show that the filters can provide an operating band from 3.1 GHz to 10.6 GHz (−10 dB bandwidth), which is suitable for ultra-wideband systems. The group delay is about 0.3 ns over the most central band and less than 0.45 ns all over the operating band. In addition, using an optimization procedure, a bandwidth of 15 GHz can be achieved with the proposed filter which is more than what was fixed by Federal Communications Commission (FCC) for UWB radio systems. Moreover, a filter constituted by combining the two proposed filters was also designed and fabricated, to improve further the band rejection.

Design of ultrawideband multilayer slot-coupled vertical microstrip transitions employing novel patch shapes

“…The antenna should be in the planar form, lightweight, and compact size, so that it can easily be embedded in the cover of communication devices. For reduce the transmission line length and the radiation losses, a simplified feeding circuit are also an important component [6][7][8][9][10].…”

“…Achieving good transmission coefficient over a maximum possible bandwidth is the main target for designing a good transition. Recently, different designs for vertical transitions have been proposed for wideband applications [1][2][3][4][5][6][7][8][9][10][11][12]. The coupling mechanism between the two layers is achieved using either an aperture (slot) or via-holes.…”

Review on UWB Bandpass Filters

“…In [48], by using parallel-coupled microstrip lines, a UWB bandpass filter with a passband from 3.1 to 10.6 GHz of less than 1 dB insertion loss is accomplished; meanwhile, the attenuation level can reach 40 dB in stopband. In order to cater for the urge demand for miniaturization, UWB bandpass filters with multilayer structures have been extensively investigated and reported [49][50][51][52][53][54][55][56][57][58]. In [57], design of an eight-pole UWB filter is demonstrated; meanwhile the proposed UWB filter not only has merits of miniature circuit size but also processes a 38.1 dB out-of-band suppression by utilizing the multilayer structure.…”

A Novel Compact Microstrip Elliptical Patch Resonator Filter with Tunable Bandwidth

“…There are some different techniques used to build microstrip bandpass filters with fixed center frequency and bandwidth, and some of these techniques are very complex. Some microstrip filters use resonator due to its excellent response [1][2][3]. Few researchers were able to control the bandwidth of the bandpass filter at a fixed center frequency by using complementary split ring resonator (CSRR) [4].…”