Dual-/tri-band bandpass filters with fully independent and controllable passband based on multipath-embedded resonators

Abstract

In this paper, dual-band and tri-band bandpass filters (BPFs) with fully independent and controllable passbands based on multipath-embedded resonators are presented. The dual-band BPF consists of two double open-ended stub-loaded terminal-shorted resonators (DOESL-TSRs) with a common via-hole connected along the symmetric plane of the filter. Based on DOESL-TSRs, a triple open-ended stub-loaded terminal-shorted resonator (TOESL-TSR) is proposed in the design of tri-band BPFs. The resonant characteristics of DOESL-TSR/TOESL-TSR are analyzed by the numerical calculation method. The measured results of the dual-band BPF show that the center frequencies (CFs) are located at 2.595 and 5.75 GHz, respectively, with 3 dB fraction bandwidth (FBWs) of 15 and 12.8%. The measured CFs of the tri-band BPF are located at 2.545, 3.775, and 5.95 GHz, respectively, with 3 dB FBWs of 9.8, 9.3, and 5.5%. Both of the filters exhibit the merits of fully independent and controllable passbands, high selectivity, and compact size.

Four Subbands from Dual Mismatched Wideband Bandpass Filter for 5G/WAS/Wi-Fi/WiMAX/WLAN Applications

“…Additionally, there is a wideband and a narrowband as a subband. Therefore, when analyzing Equation (12), the biggest BW does not mean the greater FBW, as noticed in Tables 2 and 3. The electromagnetic signal propagates at a velocity that depends on the medium to cross over and the frequency range, as Equation ( 21) says.…”

“…But researchers have adapted that principle to the radiofrequency area [11]. A large panel of studies focused on the line technique in the microwave area, terminated by open-circuit or short-circuited configurations, exist [12][13][14]. In addition, the filter structures can have multipath [12], use coupling lines [5,15], have symmetrical shapes [16], etc.…”

“…A large panel of studies focused on the line technique in the microwave area, terminated by open-circuit or short-circuited configurations, exist [12][13][14]. In addition, the filter structures can have multipath [12], use coupling lines [5,15], have symmetrical shapes [16], etc. Those possibilities often offer the right to control [17] the bandwidth (BW) and their implementation with the rest of the integration systems [18].…”