Hybrid Microstrip/Slotline Ultra-Wideband Bandpass Filter with a Controllable Notch Band

Abstract

An ultra-wideband (UWB) bandpass filter (BPF) with a controllable notch band is presented by using hybrid microstrip/slotline structure. Firstly, a slotline resonator with symmetrically loaded stubs is fed by two microstrip lines to produce a UWB bandpass filtering response. Secondly, a microstrip triangular loop resonator is externally loaded over the slotline, and a notch band is introduced in the UWB passband. The notch band is determined by the perimeter of the loop resonator. Thirdly, two patches are added as the perturbation element to the corners of the microstrip resonator to excite a pair of degenerate modes. Bandwidth of the notch band can be tuned by properly selecting the patch size. Circuit model for the microstrip resonator loaded slotline is given and studied. Finally, the filter is designed, simulated, and measured. Measured results have agreed well with the simulated ones, demonstrating that a UWB filter with a controllable notch band has been realized.

Band-stop Filtering for Electromagnetic Interference Rejection in Printed UWB Components Using Single Compact Archimedean Spiral EBG Cell

“…By implementing complementary split-ring resonators (CSRRs) without tampering with the radiator or the ground plane and generating any spurious radiation, a unique approach to realizing band-notch characteristics in UWB antennas is also studied in [23,24]. Similarly, implementing a slotted line structure [25], open-loaded stub [26], and complimentary ring resonator CRR [27] in a UWB BPF stop-band characteristics can be realized. Some other resonators can be implemented to introduce band-notch characteristics in UWB filters.…”

“…Likewise, novel configurations of two UWB planar filters with stopband behavior are designed using a cross-coupled structure [29] and radial-loaded stub resonator [30], respectively. However, these techniques [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] have some constraints in notched width controlling capabilities affecting the current distribution in the passband frequencies. As a result, the time-domain performance and radiation pattern may be influenced.…”