Wideband Microstrip Bandpass Filter Based on Quadruple Mode Ring Resonator

Abstract

A novel wideband microstrip band-pass filter is presented in this letter based on a quadruple-mode ring resonator, which is developed by introducing a stepped-impedance one-wavelength ring resonator (SORR) into a stepped-impedance half-wavelength resonator (SHR). In order to suppress the harmonic responses of the filter for a wide stop-band, two band-stop sections with asymmetrical -type structure are introduced. A prototype filter having 49.3% of 1 dB and 57.9% of 3 dB fractional bandwidth is fabricated with advantages of high selectivity and high out-of-band rejection. In the pass-band, the return loss is larger than 18.8 dB and at the centre frequency insertion loss is 0.6 dB. The experiments are in good agreement with the simulations.Index Terms-Quadruple-mode ring resonator, stepped impedance resonator (SIR), wideband band-pass filter (BPF).

Microstrip Wideband Bandpass Filter Based on Square Ring Loaded Resonator

“…The measured minimum insertion loss is about 0.9 dB and the return loss is around 15 dB. Table 1 compares the circuit size of the filter in this paper with the previous work [8] and those conventional ring resonator wideband BPFs in [9][10][11][12][13]. λ g is the wave-guided length at center frequency.…”

“…In all these structures, ring resonator filters can provide a small circuit size and thus being attractive for designer. A square ring loaded resonator (SRLR) with loaded open stubs was described for wideband BPF operation in [8], which achieves a smaller circuit size than conventional ring resonator wideband BPFs [9][10][11][12][13][14].…”

A Compact via-Less Metamaterial Wideband Bandpass Filter Using Split Circular Rings and Rectangular Stub

“…Recently, numerous bandpass filter have been proposed to accommodate the demand of wideband applications. Quadruple mode ring resonator based wideband filter gives high selectivity and high out-of-band rejection [2]. Wideband filter by using multiple ring resonator achieves low insertion loss and good sharpness factor [3].…”

Wideband Bandpass Filter With Multiple Transmission Zeros Using a Shorted Stub-Loaded Stepped-Impedance Ring Resonator

“…Various kinds of ultra-wideband (UWB) filters employing short-/open-circuited stubs, parallel-coupled lines, stepped-impedance resonator and multilayer structure [1][2][3][4][5][6][7][8] have been designed and analyzed. The short-/open-circuited stubs [1][2][3][4][5] and stepped-impedance resonator [6,7] can generate multiple resonant modes to achieve multiple transmission poles in UWB. In order to have good out-of-band performance, the cross coupling short-circuited stubs in [1] introduce a pair of transmission zeros on both sides of the passband, while the stopband width is not wide.…”

“…In order to have good out-of-band performance, the cross coupling short-circuited stubs in [1] introduce a pair of transmission zeros on both sides of the passband, while the stopband width is not wide. A bandstop filter is added to the BPFs in [2,5,7] to realize a wide stopband, but the sizes are large. The geometric structure in [10] is designed to shift the third resonance as high as possible, and the transmission zeros created by the structure are also devised to suppress the second resonance to achieve a wide upper stopband.…”