Dual-Band Bandpass Filter With Controllable Bandwidths Using Two Coupling Paths

Sch. of Electron. & Inf. Eng., South China Univ. of Technol., Guangzhou, China
IEEE Microwave and Wireless Components Letters (Impact Factor: 1.7). 12/2010; 20(11):616 - 618. DOI: 10.1109/LMWC.2010.2066553
Source: IEEE Xplore


This letter presents the designs of dual-band bandpass filters using two coupling paths to control the bandwidth of each passband. One coupling path only delivers signals at the upper passband frequency whereas the other one couple signals at both passbands. Utilizing this method, the two bandwidths can be adjusted. The filters make use of stub-loaded resonators and it is convenient to tune the passband frequencies. Therefore, both the frequency and bandwidth of each passband can be easily controlled. For demonstration purpose, two example filters are implemented with different bandwidths. The experimental results are presented to verify the proposed method.

Download full-text


Available from: Xiu Yin Zhang, Aug 21, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study proposes a concurrent dual-band filter that consists of two single-band filters using quarter-wavelength resonators. The two single-band filters, having different feeding structures, can be designed separately. The lower-band filter has tapped feeding structure and the higher-band filter has coupling feeding structure where the input/output line and the lower-band resonator constitute a feeding coupling line. Therefore, commonly used T-junction or other dual-band impedance transformer is avoided. The proposed filter is easy to design and has a compact size. A dual-band filter, operated in 0.9 GHz and 1.9 GHz, is designed to validate the proposed structure. Index Terms—Dual-band filter, quarter wavelength resonator, stepped impedance resonator, hybrid feeding structure.
    Preview · Article · Jan 2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents a compact high isolation dual-band bandpass filter using dual mode resonators and lumped elements for wireless applications. Multiple Transmission Ze-ros(TZs) are created to improve the selectivity and isolation between two bands using inductive cross coupling. The symmetrical coupling mechanism is realized for both the bands to achieve isolation better than 33dB. The designed filter being very compact will be suitable for wireless applications. Measured results agree well with the simulation results.
    No preview · Article · Jan 2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: We present a balanced dual-band bandpass filter (BPF). The proposed filter is established by using half-wavelength resonators loaded with a lumped series resonator. To verify the operation of the proposed resonator, the differential-and common-mode equivalent circuits are extracted and studied. Moreover, to enhance the common-mode suppression, a lumped resistor is added to the half-wavelength resonator with the lumped series resonator. Based on the proposed circuit, the desired differential-mode dual-band response is easily realized and the level of common-mode noise is minimized simultaneously. Two-pole balanced dual-band BPF with center frequencies of 1.3 GHz and 2.75 GHz is designed and the measured results agree well with simulated results.
    No preview · Article · Jan 2011
Show more