Design and analysis of compact BPF with dual notch bands based on stepped‐impedance resonator for UWB applications

Abstract

In this study, a compact ultra‐wide band (UWB) bandpass filter (BPF) with improved out‐of‐band performance and dual notch bands operation is suggested and its design and analysis procedure is discussed. In the suggested BPF, etching slot in the ground plane is employ to meliorate the out‐of band efficiency of the filter. In addition, four short‐circuited folded stubs are used to enhance the selectivity of the BPF at its cutoff frequencies. The upper stop‐band with more than 20dB attenuation level extends to 20 GHz. Dual notch bands function is added to the performance of the filter by coupling two stepped‐impedance resonator (SIR) to the filter primary resonator. It is shown that the frequency locations of the notch bands can be adjusted by varying the impedance ratio of the embedded SIR. The constructed prototype has a small size and is able to coverage frequency band of 2.97–11.18 GHz with dual notch bands function at 5.5–6.3 and 7.84–9.06 GHz, which suppresses the interference between UWB spectrum with WLAN and satellite communication frequency bands, respectively. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:672–674, 2017

A miniaturized low‐cost microstrip‐to‐coplanar waveguide transition‐based ultra‐wideband bandpass filter with multiple transmission zeros

“…It can be observed from column 1 of Table 1 below that the proposed structure is developed on a low‐cost dielectric unlike others 2‐10,12,13 . Column 2 indicates that the proposed structure meets the FCC passband requirement of 3.1 to 10.6 GHz comfortably.…”

“…The presence of TZs at either passband edge is very crucial to the frequency characteristics of any BPF for its enhanced selectivity. From column 3, it is observed that the proposed structure possesses TZs at both the passband edges unlike, 2,3,7‐9,11‐13 which do not possess TZ at either passband edges, whereas 4‐6,10 possess TZ at only one passband edge. Column 4 depicts that dual notches of the proposed structure have good attenuation (>15 dB) at 6.1 (C band) and 8.1 GHz (X band).…”

“…This spectrum is also home to other RF sources like WLAN, C, X band, and so on, which are concentrated pockets of high power and often act as sources of interference to the UWB systems. For these UWB devices to operate interference free, researchers have designed and developed UWB‐bandpass filters (BPFs) with integrated multiple stopband characteristics 2‐13 . Dual passband notches were developed in these UWB filters using stubs acting on the wave cancellation principle, 2,3 slots engraved in the microstrip, 4,5 stepped impedance resonators (SIRs) placed along microstrip 6 or feedline, 7 SIR in the form of E‐shaped resonator, 8 simplified composite right/left‐handed (SCRLH) resonator 9 placed adjacent to microstrip.…”

“…Other structures developed dual notches using multiple stubs attached to patch, 10 electromagnetic bandgap structure placed closed to feedline, 11 or combination of stubs with slot 12 or stubs with defected ground structures 13 . Most of them are developed on high‐cost dielectric, 2‐10,12,13 have large size, 2‐13 possess vias that make the geometry complex, 6‐9,11,12 and lack transmission zeros (TZs) 2‐13 …”

Triple Notches Bandstop Microstrip Filter Based on Archimedean Spiral Electromagnetic Bandgap Structure

“…So far, scholars have applied artificial electromagnetic structures to the design of microstrip filters. The traditional methods to realize notch microstrip filters such as using open or short stub loaded resonators [2,3]; using stepped impedance resonators [4,5]; using multimode resonators [6][7][8] such as T shaped resonators [9][10][11], E shaped resonators [12,13], ring resonators [14], Hilbert-Fork Resonators [15]; coupling resonators are designed by coupling structure between microstrips [16,17]. In addition, microstrip notch filters can be realized by constructing a defective grounding structure (DGS) [18,19].…”