Design of Dual- and Triple-Passband Filters Using Alternately Cascaded Multiband Resonators

Abstract

A novel method for designing multiband bandpass filters has been proposed in this paper. Coupling structures with both Chebyshev and quasi-elliptic frequency responses are presented to achieve dual-and triple-band characteristics without a significant increase in circuit size. The design concept is to add some extra coupled resonator sections in a single-circuit filter to increase the degrees of freedom in extracting coupling coefficients of a multiband filter and, therefore, the filter is capable of realizing the specifications of coupling coefficients at all passbands. To verify the presented concept, four experimental examples of filters with a dual-band Chebyshev, triple-band Chebyshev, dual-band quasi-elliptic, and triple-band quasi-elliptic response have been designed and fabricated with microstrip technology. The measured results are in good agreement with the full-wave simulation results.

Compact Split Ring Sir Bandpass Filters With Dual and Tri-Band

“…In this paper, split ring tri and quad-section SIR bandpass filters with dual-band operation are presented, and compared with dual-band filters with two sets of different resonators or two paths coupling, the new filter sizes are greatly reduced. The proposed SIR dual-band filters have size reduction of about 75% and 77% compared with [2] and [12], respectively. Split ring SIR bandpass filters with triband operation by using two sets of different resonators with two-path coupling are also proposed, and which have size reduction of about 81% and 68.3% compared with [8] and [12], respectively.…”

“…The proposed SIR dual-band filters have size reduction of about 75% and 77% compared with [2] and [12], respectively. Split ring SIR bandpass filters with triband operation by using two sets of different resonators with two-path coupling are also proposed, and which have size reduction of about 81% and 68.3% compared with [8] and [12], respectively. The new designs are demonstrated by experiment.…”

“…SIR also can be used to design tri-band even multiband filters for tuning the higher order resonant modes conveniently. The deficiency of this kind of resonator is its resonant frequencies are dependent, and transmission zeros are difficult to implement, especially for the fundamental SIR Commonly, there are the following methods for dual-and multiband filter design: the first is using cascade resonators including the stepped impedance resonator [7,8,12], the second is using two sets of different resonators with two-path coupling [3], the third is using new resonator [2], and the fourth is using dual-mode [1,2] or multimode resonator. In this paper, split ring tri and quad-section SIR bandpass filters with dual-band operation are presented, and compared with dual-band filters with two sets of different resonators or two paths coupling, the new filter sizes are greatly reduced.…”

Compact Multiband Transversal Bandpass Filters With Multiple Transmission Zeroes

“…In [10], since the first and the second passband were achieved by the stub-loaded resonator, the center frequencies of two passbands cannot be controlled independently. In [11], the triple-band filter was implemented by alternately cascaded multiband resonators. However, the number of resonators results in large circuit size and poor insertion loss.…”

Dual-Mode CPW-Fed Double Square-Loop Resonators for Wlan and Wimax Tri-Band Design

“…The multi-band BPFs play an important role in a multi-band transceiver, such as dual-band [1][2][3][4], tri-band [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] and quad-band [20][21][22] filters.…”