scholarly journals Compact Ultra-Wideband Bandpass Filters Achieved by Using a Stub-Loaded Stepped Impedance Resonator

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 209 ◽  
Author(s):  
Min-Hang Weng ◽  
Fu-Zhong Zheng ◽  
Hong-Zheng Lai ◽  
Shih-Kun Liu

In this paper, we develop a bandpass filter using a stub-loaded stepped impedance resonator (SLSIR) and calculate the even and odd resonant modes of this type of resonator using the input impedance/admittance analysis. In this study, two impedance ratios and two length ratios are operated as the design parameters for controlling the resonant modes of the SLSIR. Several resonant mode variation curves operating three resonant modes with different impedance ratios and two length ratios are developed. By tuning the desired impedance ratios and length ratios of the SLSIRs, compact ultra-wideband (UWB) bandpass filters (BPFs) can be achieved. Two examples of the UWB BPFs are designed in this study. The first example is UWB filter with a wide stopband and the second one is dual UWB BPF, namely, with UWB performance and a notch band. The first filter is designed for a UWB response from 3.1 to 5.26 GHz having a stopband from 5.3 to 11 GHz, with an attenuation level better than 18 dB. The second filter example is a dual UWB BPF with the frequency range from 3.1 to 5 GHz and 6 to 10.1 GHz using two sets of the proposed SLSIR. The measured results have insertion loss of less than 1 dB, and return loss greater than 10 dB. Furthermore, the coupling structures and open stub of the SLSIR also provide several transmission zeros at the skirt of the passbands for improving the passband selectivity.

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Wei-Qiang Pan ◽  
Xiao-Lan Zhao ◽  
Yao Zhang ◽  
Jin-Xu Xu

This paper presents a novel method to design dual-band bandpass filters with tunable lower passband and fixed upper passband. It utilizes a trimode resonator with three controllable resonant modes. Discriminating coupling is used to suppress the unwanted mode to avoid the interference. Varactors are utilized to realize tunable responses. The bandwidth of the two bands can be controlled individually. Transmission zeros are generated near the passband edges, resulting in high selectivity. For demonstration, a tunable bandpass filter is implemented. Good agreement between the prediction and measurement validates the proposed method.


Author(s):  
Lei Bai ◽  
Yiqi Zhuang ◽  
Zhibin Zeng

Abstract In this paper, a compact quintuple notched-band ultra-wideband bandpass filter with high selectivity and wide bandwidth is proposed. The filter adopts an approximate closed-loop C-shaped stepped impedance resonator to generate triple notched bands, and uses Hilbert fractal curve slit and L-shaped resonator to create single notched band, respectively. Multiple notched-band are centered at 5.29, 6.61, 7.92, 8.95, and 9.93 GHz to eliminate undesired interference from coexisting wireless services of WLAN, C-band, and X-band. Additionally, two transmission zeros are introduced to enhance the sharp skirt selectivity up to 0.944. This filter could exhibit high sharp selectivity and wider bandwidth simultaneously. The filter is fabricated on a RT/Duroid 5880 substrate (ɛ r = 2.2 and thickness = 0.787 mm) and measured to verify the simulation results. Both simulation and measurement are in well agreement, showing the good performance of the filter.


2019 ◽  
Vol 28 (13) ◽  
pp. 1920008
Author(s):  
Xiaodong Xie ◽  
Zhizhan Yang ◽  
Mingxing Deng

A multi-stub loaded loop resonator (MSLLR) is proposed in this paper, which exhibits five main resonant modes of interest. Then, an ultra-wideband (UWB) bandpass filter is developed on it. Through direct source/load coupling, two transmission zeros can be created at both sides of the passband of the filter, which improves its frequency selectivity. The measured results of the fabricated filter show that its bandwidth can cover the UWB frequency range and the return loss in the passband is greater than 12.9[Formula: see text]dB. Frequency selectivity is improved due to two transmission zeros at both sides of the passband. Group delay variation is less than 0.48[Formula: see text]ns in the passband, which is relatively flat.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Yingsong Li ◽  
Wenxing Li ◽  
Qiubo Ye

A coplanar waveguide (CPW)-fed circular slot antenna with wide tunable dual band-notched function and frequency reconfigurable characteristic is designed, and its performance is verified experimentally for ultra-wideband (UWB) communication applications. The dual band-notched function is achieved by using a T-shaped stepped impedance resonator (T-SIR) inserted inside the circular ring radiation patch and by etching a parallel stub loaded resonator (PSLR) in the CPW transmission line, while the wide tunable bands can be implemented by adjusting the dimensions of the T-SIR and the PSLR. The notch band reconfigurable characteristic is realized by integrating three switches into the T-SIR and the PSLR. The numerical and experimental results show that the proposed antenna has a wide bandwidth ranging from 2.7 GHz to 12 GHz with voltage standing wave ratio (VSWR) less than 2, except for the two notch bands operating at 3.8–5.9 GHz and 7.7–9.2 GHz, respectively. In addition, the proposed antenna has been optimized to a compact size and can provide omnidirectional radiation patterns, which are suitable for UWB communication applications.


Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1316 ◽  
Author(s):  
Min-Hang Weng ◽  
Che-Wei Hsu ◽  
Siang-Wen Lan ◽  
Ru-Yuan Yang

This paper presents an ultra-wideband bandpass filter (UWB-BPF) with a notch band and a wide upper stopband. Two pairs of half-wavelength high-impedance line resonators tightly and strongly coupled to the input/output lines are used to provide the wideband responses. The first UWB responses of 3.4–5.0 GHz and the second UWB of 6.0–10.0 GHz are designed independently first and then combined together for the application of a direct-sequence ultra-wideband bandpass (DS-UWB) system. Without using any extra bandstop structure, a notch band at 5.2 GHz can be obtained. The fabricated UWB-BPF with a compact circuit size exhibits good passband performances including insertion losses of 1 ± 0.3 and 2 ± 0.4 dB for first and second passbands, respectively, a high isolation at 5.2 GHz with an attenuation level of 22.7 dB, and wide upper stopband responses from 11 GHz to 19 GHz, simultaneously. The measured results also exhibit good agreement with the simulated results.


2011 ◽  
Vol 53 (12) ◽  
pp. 2920-2922 ◽  
Author(s):  
Liang Zhou ◽  
Shao-bin Liu ◽  
Xiang-kun Kong ◽  
Hai-feng Zhang ◽  
Ya-nan Guo

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 416 ◽  
Author(s):  
Fang Yan ◽  
Yong Mao Huang ◽  
Tao Huang ◽  
Shuai Ding ◽  
Kenian Wang ◽  
...  

Multi-function wireless systems demand multi-channel transmit/receive (TR) modules, particularly as multiple functions are required to operate simultaneously. In each channel, passive components, including bandpass filters, must be compact, or at least transversely compact; thus, the entire circuitry of the channel will be slender, and consequently multiple channels can be parallel-arranged conveniently. In this work, single-ended and balanced bandpass filters for multi-channel applications are presented. As a unique resonator, the U-shaped stepped impedance resonator (USIR) can achieve size miniaturization compared with its corresponding uniform impedance resonator (UIR) counterpart. Hence, with the utilization of USIRs, the proposed bandpass filters are able to acquire compact transverse sizes. Moreover, by using the source–load coupling scheme, two transmission zeros (TZs) are respectively generated at the lower and upper sides of the passbands, which is useful for improvement of the selectivity performance. In addition, spurlines are introduced at the input and output ports to produce another TZ to further enhance the stopband performance, which cannot be acquired by the UIR or stepped impedance resonator (SIR). To verify the aforementioned idea, one single-ended and one balanced bandpass filter are implemented, with experimental results in good agreement with the corresponding simulations. Meanwhile, as compared with some similar works, the proposed balanced filter achieves compact transverse size, sharp selectivity skirt, and wide stopbands up to the fourth-order harmonic with suppression over 20 dB, which illustrates its suitability for differential signal transmission application in microwave circuits and systems.


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