Substrate Integrated Waveguide Diplexer Based on Circular Triplet Combline Filters

Abstract

Abstract-The design of substrate integrated waveguide (SIW) diplexers, based on combline triplet sections with transmission zeros (TZs) placed below and above the passband, is presented. In order to control the location of the TZs, positive and negative couplings are conveniently provided. A highly compact implementation based on circular substrate integrated coaxial resonators is proposed. An X-band diplexer with channel center frequencies at 9.5 and 10.5 GHz and absolute bandwidths of 400 MHz is designed. The structure shows important advantages in terms of size reduction, while keeping good insertion losses as well as high rejection and isolation levels.Index Terms-Combline filters, diplexer, substrate integrated waveguide (SIW), transmission zeros (TZs).

Compact Qmsiw Diplexer With High Isolation

“…Comparison between literatures [10- 13] and the proposed diplexer is listed in Table 2. In [10], a combline triplet diplexer with high rejection performance is obtained, but the circuit size is larger than the proposed one. In [11], the diplexer has a compact size with high selectivity and improved out-of-band rejection.…”

Miniaturized Substrate Integrated Waveguide Diplexer Using Open Complementary Split Ring Resonators

“…Among them, the evanescent-mode technique attracts an extreme attention because of easy etching some components on the top or bottom metal surface of the SIW structure [7][8][9][10]. According to this theory, an additional forward passband at the frequency range below the waveguide cutoff could be achieved by loading the electric dipoles on the metal cover of the SIW structure.…”

“…This component provides a high bandisolation between two different output ports to avoid interference between each other. In order to achieve a few desired specifications for a high-performance diplexer in terms of low insertion losses, strong channel rejection and high isolation, this device can be realized by different filter configurations [5][6][7][8][9][10]. The SIW structures are suitable to realize essential filter elements of the diplexers because of the advantage of these structures.…”

Cross-coupled bandpass filter based on circular substrate integrated waveguide resonator

“…The conventional SIW cavities are rectangle structure. However, considering the size, Q-factor and design flexibility, circular SIW resonators and their applications to the passive components are presented [3,4,5]. In [6], a crosscoupled CSIW filter is presented with a transmission zero (TZ) implemented under the passband, but the filter has low selectivity upper the passband, high insertion loss and the perceptual window is hard to be adjusted.…”