Mona Yazdani Shavakand - First Author’s Affiliation and Short Address
Javad Ahmadi-Shokouh - Second Author’s Affiliation and Short Address
Fatemeh Kazemi - Third Author’s Affiliation and Short Address

In this paper, a novel type of multiple-mode resonator (MMR) is analyzed and used to design ultrawideband (UWB) band-pass filter. The MMR consists of a rectangular loop resonator (RLR) and a short circuit stub, which has five main resonance frequencies and two transmission zeros (TZs). The transmission zero is near the cutoff frequency in upper stopband, thus sharp skirt characteristic is created. In order to improve the coupling degree, two interdigital coupled-lines are placed in the input and output sides for feeding MMR. The simulated results demonstrate that this UWB filter has return loss better than 10 dB in passband, good stopband suppression higher than 10 dB from 11.35 to 16.87 GHz, and 26.4, 38.2 dB/GHz attenuation slope at the lower and upper transition bands, respectively. The dimension of this filter is about 0.68 g ×0.11 g and bandwidth is 119.7%. The group delay for this filter is obtained less than 0.3 ns. Finally, the UWB filter is fabricated and there is a good agreement between the EMsimulated and the measured results is obtained.

Band-pass filter (BPF), compact size, multiple-mode resonator (MMR), rectangular loop resonator, ultra-wideband (UWB)