Design of a Compact 5.7-5.9 GHZ Filter Based on CRLH Resonator Units

Abstract

A compact substrate integrated waveguide (SIW) filter based on composite right/lefthanded (CRLH) resonator units is implemented in this paper. The filter is composed of two CRLH resonator units serially connected by a SIW transmission line unit. The structure of the filter and equivalent circuit transmission behavior are analyzed, and a novel design method by optimizing the length and width of the interdigital metal slots to decrease the filter operation frequency is proposed. To further demonstrate the design theory and performance of the proposed filter, the filter was designed and fabricated on an RT6010 dielectric material. The measurement results show that the proposed filter works at a center frequency of 5.8 GHz with 200 MHz bandwidth The insertion loss is 2.3 dB, and the filter size is only 10 mm × 7.4 mm.

Narrowband LTCC Filter With Length-Reduced End-Coupled Resonators

“…Performances comparisons with other narrowband implementations are listed in Table 2. The implemented BPF has the smallest average passband insertion loss, greatest size reduction, and narrowest FBW among BPFs in [1][2][3][4][5][6][7][8][9][10][11][12]. Although BPFs in [13,14] achieved a smaller size and narrower [13], and extra via transition is needed with a higher passband insertion loss [14].…”

“…Narrowband bandpass filters (BPFs) have been widely adopted and increasingly required for military phased array radar transceivers. Narrowband BPFs can be constructed with combined structures [1], split ring resonator [2,3], resistor-loaded resonator [4], cross-coupling structure [5], substrate integrated waveguide [6,7], open-loop resonator [8], right-left hand resonator [9], and end-coupled resonators [10][11][12]. Traditional planar end-coupled BPF is constructed with cascaded half-wavelength resonators, and the interconnection between adjacent resonators is via end-coupling effect.…”

“…Secondly, the coupling gap distance between adjacent resonators is limited less than 50 µm according to printed circuit board (PCB) fabrication process, which is not enough for filter design. BPFs in [8][9][10] solved the above coupling gap problem by placing resonators on different layers, but helped little for size reduction as the length of resonator was not reduced. BPFs in [13,14] achieved 80% size reduction using a stacked structure in a low temperature co-fired ceramic (LTCC) substrate.…”

Miniaturization Trends in Substrate Integrated Waveguide (SIW) Filters: A Review

“…Furthermore, a third-order filter is also designed with a centre frequency of 6.06 GHz and a fractional bandwidth of 6.4%. It has the insertion loss of 1.86 dB and return loss FIGURE 29: CLRH-based SIW cavity filter [73]. less than 15.4 dB.…”

“…In [73], a CLRH-based SIW bandpass is reported. The filter is designed by using CLRH structures in combination with SIW technology.…”