Compact metamaterial unit-cell based on stepped-impedance resonator technique and its application to miniaturize substrate integrated waveguide filter and diplexer

Abstract

In this article, a new miniaturized metamaterial unit‐cell using stepped‐impedance resonator technique is proposed. The proposed unit‐cell is used to miniaturize the physical size of the conventional complementary split‐ring resonators (CSRRs). In the proposed unit‐cell which is called complementary G‐shaped resonator (CGR), the slot line in the conventional circular CSRR is replaced with the stepped‐impedance slot line. As well as, by carving two trapezoidal shapes inside the inner ring, the resonance frequency of the proposed CGR unit‐cell has been more decreased. Compared to the conventional circular CSRR structure, the electrical size of the proposed CGR is decreased and miniaturization is occurred. To investigate the performance of the proposed CGR unit‐cell in the size reduction, two substrate integrated waveguide filters and a diplexer are designed. To validate the proposed miniaturization technique, the designed filters and diplexer loaded by the CGR unit‐cell are fabricated and measured. The measured results are in a good agreement with the simulated ones. The results shows that, a miniaturization factor about 0.69 is achieved.

Half-Mode Substrate Integrated Waveguide Evanescent-Mode Filters With Slots-Embedded Complementary Split-Ring Resonators for Depressed Machining Tolerance Sensitivity

“…Hence, as the proposed one-pole and two-pole Type-III HMSIW-SECSRR filters are redesigned with a center frequency around 5.5 GHz, its insertion loss would be 0.52 + 0.141 = 0.661 dB and 0.96 + 0.141 = 1.101 dB, respectively, which is still much lower than that in [8,10,11]. Moreover, the proposed HMSIW-SECSRR filters also achieve similar return loss performance to those in [8][9][10], only worse than those in [11,12]. Hence, in a word, the proposed filters exhibit good insertion loss, compact size, and reduced fabrication tolerance sensitivity, which indicates promising practicability for RF and microwave applications.…”

“…A modified CSRR (MCSRR) is proposed in [10] by inner extending the split in menderline shape for HMSIW filter implementation. Moreover, the fractal open CSRR (FOCSRR) and G-shaped resonator (CGR) are presented in [11] and [12] to reduce the circuitry physical sizes, respectively. Firstly, it can be easily obtained that compared with all the reported filters in Table 2, the proposed HMSIW-SECSRR filters are with the smallest relative electrical size and smallest insertion loss, as well as reduced fabrication tolerance sensitivity.…”

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

“…In [66], different types of SIMMS geometries are reported to develop miniaturized SIW-based filters and diplexers. same split-ring resonator is modified to develop a G-shaped SIMMS.…”

“…Therefore, radiation can be expected from the upper copper-layer of the resonator. The forward radiation loss can be be computed from Equation ( 6) [66]. It is shown that the reported filter has a radiation loss of less than 0.0012.…”