UWB Bandpass Filter Based on Ring Resonator

Abstract

A new ultra‐wideband bandpass filter is proposed, with a ring resonator and two stepped‐impedance stubs to provide good wideband filtering performance and sharp rejection skirts. Interdigital coupled lines are placed at both ends of the ring resonator as input and output feed lines. The use of interdigital coupled lines makes it possible for the first three resonances of the ring resonator to be closer to wideband characteristics. By cutting apertures in the ground plane under the interdigital coupled lines, the coupling effect between the feed lines and the ring resonator can be increased, so that the passband characteristics can be improved. By adding two stepped‐impedance stubs to the ring resonator, sharp rejection skirts can be obtained in the passband. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2047–2051, 2013

UWB bandpass filters with triple notched band characteristics implemented using wave cancellation technique

“…Numerous techniques have been proposed to date in the development of UWB bandpass filters, e.g. multiple‐mode resonator (MMR), hybrid microstrip/coplanar‐waveguide (CPW) techniques, coupled line structure, defected ground structure (DGS), multilayer‐coupled structure, electronic band‐gap (EBG) structure loaded techniques, optimum short‐circuited stub, and cascaded low‐pass/high‐pass filters . The major impediment to the wide adoption of UWB technology is the issue of narrowband interferences that co‐exist in the UWB spectrum, such as WLAN at 5.2 and 5.8 GHz, and satellite communication systems at 8 GHz.…”

A miniaturized microstrip‐to‐CPW transition based UWB‐BPF with sharp roll‐off and minimum insertion loss

“…Research on design and development of ultrawideband (UWB) bandpass filters (BPF) took an exponential growth as the release of unlicensed UWB spectrum (3.1–10.6 GHz) by the Federal Communications Commission (FCC) for hand held devices in indoor environment . The various structures proposed in this context used different principles for UWB generation . The most common method involved in design of an UWB‐BPF is the use of a multiple mode resonator (MMR) which possesses the flexibility of placing resonant modes at frequencies of interest in the passband .…”

Wideband bandpass filter with controllable bandwidth and high selectivity using two different types of resonators

“…Recently, there has been increased interest in wideband bandpass filter (BPFs) for application in modern wireless communication systems, great efforts have been performed to realize various kinds of wideband BPFs [1][2][3][4][5][6][7][8]. In [1], an ultrawideband (UWB) BPF with one of the outer coupled lines shorted to ground is proposed to exhibit two new transmission zeros and increase the selectivity significantly.…”

“…However, the selectivity at low-edge of the passband has a large space to be increased. In [6], an UWB BPF with a ring resonator and two steppedimpedance stubs is presented to provide good wideband filtering performance and sharp rejection skirts. To improve the selectivity, one folded half-wavelength resonator in the middle and two quarter-wavelength resonators are used to create five transmission zeros due to the cross coupling in Ref.…”

“…Microwave integrated resonators are widely used in microwave and milli-metric components, which include filters [1][2][3], oscillators [4][5][6], and antennas [7,8]. One form of the integrated resonator is the coplanar waveguide (cpw) radial resonator [9] and more recently the diamond resonator which has been shown to occupy 55% less chip area than a comparable radial stub resonator [10].…”