High‐selective triple‐mode SIW bandpass filter using higher‐order resonant modes

Zhang

Micro & Optical Tech Letters

et al. 2022

A compact triple‐mode (TM) bandpass filter (BPF) is designed based on the proposed dual capacitively‐loaded (DCL) substrate‐integrated waveguide (SIW) resonator. Two identical T‐shaped grounded striplines are inserted into a square SIW cavity to generate a capacitively loading effect without damaging cavity surface integrity, which contributes to maintaining EM‐shielding capability. By adjusting the size and position of the DCL structure, the first three resonant modes, including TE101, TE201, and TE301 are easily controlled to design a TM‐BPF. A transmission zero (TZ) is introduced by the grounded striplines and flexibly controlled. TZ is tuned to suppress the TE102 mode to acquire a wide upper rejection band. Furthermore, the filter design procedures are presented in the context under specified filter performance. Finally, to verify the proposed design method, an example of self‐packaged TM‐BPF at 6 GHz with a good lower stopband and a wide upper rejection band is designed, fabricated, and measured. The measured results are in good agreement with simulated ones.

Section: Introductionmentioning

confidence: 99%

A compact self‐packaged triple‐mode bandpass filter using dual capacitively‐loaded substrate‐integrated waveguide resonator

Zhang

Micro & Optical Tech Letters

et al. 2022

“…Third order topologies are also possible by embedding additional resonant elements into a dual-mode SIW cavity, as very recently reported in [125] and [126]: the structure reported in [125] implements a third order transversal topology thanks to the presence of a capacitively loaded partial-height post located at the center of the cavity; on the other hand, the structure proposed in [126] utilizes the combination of a dualmode cavity with a stripline resonator that can be modelled with a topology where the central resonator is extracted and connected to the main line (between the other two resonators) by means of a nonresonanting node.…”

Section: Emerging Technique Pseudo-elliptic Realizationsmentioning

confidence: 86%

Emerging Trends in Techniques and Technology as Applied to Filter Design

et al. 2021

In the last decade, the filter community has innovated both design techniques and the technology used for practical implementation. In design, the philosophy has become "if you can't avoid it, use it", a very practical engineering approach. Modes previously deemed spurious are intentionally used to create in-line networks incorporating real or imaginary transmission zeros and also reduce the number of components and thus further miniaturize; spurious responses are re-routed to increase the passband width or stopband width, frequency variation in couplings is used to create complex transfer functions, with all of these developments using what was previously avoided. Clever implementations of baluns into passive and active networks is resulting in a new generation of noise-immune filters for 5G and beyond. Finally, the use of a diakoptic approach to synthesis has appeared an evolving approach in which small blocks ("singlets", "doublets", etc.) are cascaded to implement larger networks, (reducing the need for very complex synthesis), with this new approach promising a large impact on the implementation of practical structures. Filter technology has migrated towards "observe it and then adapt it", pragmatically repurposing tools not specifically originally intended for the applications. Combinations of surface wave and bulk wave resonators with L-C networks are improving the loss characteristics of filters in the region below 2 GHz. Lightweight alloys and other materials designed for spacecraft are being used in filters intended for space, to provide temperature stability without the use of heavy alloys such as Invar. Fully-enclosed waveguide is being replaced in some cases by planar and quasiplanar structures propagating quasi-waveguide modes. This is generically referred to as SIW (Substrate Integrated Waveguide). Active filters trade noise figure for insertion loss but perhaps will offer advantage in terms of size and chip-level implementation. Finally, the era of reconfiguration might be approaching, as the basic networks are evolving, perhaps lacking only the appearance of lower-loss, higher-IP solid-state tuning elements.

“…Various antennas have been developed to obtain excellent filtering performances, including Yagi Uda antennas [1], dielectric resonator antennas [2][3][4][5][6], microstrip patch antennas [7][8][9][10][11], and substrate integrated waveguide (SIW) antennas. Due to the virtues of low loss and high radiation efficiency, SIW has been widely applied to design excellent filtering antennas [12][13][14][15][16][17][18][19][20][21][22][23][24][25]. By vertically stacking the resonators, multilayered 3-D configurations are designed in [14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

A Low-Profile Half-Mode Substrate Integrated Waveguide Filtering Antenna With High Frequency Selectivity

Wang¹,

Zhao²,

Li³

et al. 2021

PIER Letters

A low-profile half-mode substrate integrated waveguide (HMSIW) filtering antenna with high frequency selectivity is proposed in this letter. The proposed antenna with a height of 0.014λ 0 (λ 0 is the free-space wavelength) consists of a slot-loaded HMSIW cavity, two parasitic patches, and five shorting pins. An upper-edge radiation null is generated by the interaction between the HMSIW cavity and parasitic patches. A rectangular slot etched on the HMSIW cavity is adopted to generate another null to improve the filtering performances at the upper stopband. Besides, the radiation in the lower stopband is suppressed by two nulls which emerge due to placing shorting pins under two parasitic patches. Thus, four radiation nulls can be obtained to enhance the frequency selectivity. The measured results illustrate that the proposed antenna provides an impedance bandwidth of 4.3% ranging from 2.74 to 2.86 GHz and a peak gain of 6.76 dBi during the operating frequency band. Moreover, four radiation nulls appear at 2.34, 2.56, 3, and 3.24 GHz in the lower and upper stopbands.