Browsing by Author "Xu, Ruimin"

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A pi-type Isolation Network for Improvement of Matching and Isolation in Reconfigurable Multifunctional Bandpass Filter
(2019-01-01)
Zhu, Xu
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Yang, Tao
;
Chi, Pei-Ling
;
Xu, Ruimin
;
交大名義發表
In this paper, a method for improving the output impedance match and isolation between output ports of the reconfigurable single-to-balanced (SE-BAL), power-dividing (PD) and single-ended (SE) multifunctional filter is presented. By adding the varactor-tuned pi-type isolation network to the outputs of the tunable multifunctional filter, both the matching and isolation at the output ports are improved to a large degree over the full tuning range. Compared to the original standalone multifunctional filter, the measured output return loss and isolation of the filter with pi-type isolation network are improved by more than 10 dB at center frequency of each tuning state under the SE-BAL and PD filtering mode, while the measured output return loss and isolation for the SE filtering mode still keeps better than -20 dB in the whole tuning range.
Folded Substrate Integrated Waveguide Based Composite Right/Left-Handed Transmission Line and Its Application to Partial H-Plane Filters
(2013-02-01)
Yang, Tao
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Chi, Pei-Ling
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Xu, Ruimin
;
Lin, Weigan
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電機資訊學士班
Composite right/left-handed (CRLH) transmission line structures based on the folded substrate integrated waveguide (FSIW) are presented and discussed in this paper. This FSIW-based CRLH (FSIW-CRLH) transmission line exhibits much lower cut-off frequencies as compared to the ordinary FSIW of the same footprint, and furthermore, it requires only one-half width of the conventional substrate integrated waveguide (SIW) based CRLH (SIW-CRLH) transmission lines while possessing the same dispersion characteristics. In addition, the proposed structure offers the advantage of a high quality factor for preventing the guided-wave circuits from radiation as suffered in the previous open CRLH transmission line structures when operated in the fast-wave region. All of the aforementioned properties lend the proposed FSIW-based CRLH transmission lines best suited to miniaturized and guided-wave microwave applications. In this paper, a comprehensive study on the FSIW-CRLH transmission structures is conducted by means of its dispersion relation and Bloch impedance. In addition, two partial H-plane filters are implemented here to demonstrate the capabilities of miniaturization and high quality factor based on the proposed FSIW-CRLH structures. The resultant filters are shown to have about 80% size reduction as compared to the conventional FSIW filters, and 59% size reduction as compared to the SIW-CRLH filters. To the best of our knowledge, it is the first time that the partial H-plane filters are implemented utilizing both the dispersion behavior of the CRLH transmission structures and the structural benefits of the FSIW configuration.
Novel Evanescent-Mode Cavity Filter With Reconfigurable Rat-Race Coupler, Quadrature Coupler and Multi-Pole Filtering Functions
(2020-01-01)
Lai, Junchen
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Yang, Tao
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Chi, Pei-Ling
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Xu, Ruimin
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電機工程學系
A novel evanescent-mode cavity filter with multiple reconfigurable functions including filtering rat-race coupler, filtering quadrature coupler and multi-pole filtering is proposed in this paper. It simply consists of four substrate integrated waveguide (SIW) evanescent-mode cavity resonators which are arranged in a ring loop. By loading piezoelectric actuators on top of each resonator and inserting varactors between adjacent resonators, the structure can achieve multiple reconfigurable functions among filtering rat-race coupler, filtering quadrature coupler and single-ended multi-pole filters, in addition to continuously frequency, independent bandwidth, and power-division tuning. Measurement shows that the filtering quadrature coupler corves a frequency range of 2.08-3.00 GHz with insertion loss of 2.99 & x00B1; 0.31dB, while the filtering rat-race coupler corves a frequency range of 2.31-2.71 GHz with insertion loss of 2.97 & x00B1; 0.13dB; The single-ended filter can be switched among two-pole, three-pole, and four-pole with frequency range of 2.38 to 3.01 GHz, 2.47 to 3.08 GHz and 2.53 to 3.00 GHz, respectively. Good agreement is obtained between simulated and measured results.
Novel Reconfigurable Filtering Rat-Race Coupler, Branch-Line Coupler, and Multiorder Bandpass Filter With Frequency, Bandwidth, and Power Division Ratio Control
(2020-04-01)
Zhu, Xu
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Yang, Tao
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Chi, Pei-Ling
;
Xu, Ruimin
;
電機工程學系
In this article, for the first time, a novel four-port coupler with reconfigurable multifunctions of filtering rat-race coupler (FRC), filtering branch-line coupler (FBC), and conventional single-ended two-port multipole bandpass filter (BPF) is proposed. It simply consists of four varactor-loaded stepped-impedance resonators that are arranged symmetrically. Through appropriate coupling-type (electrical coupling or magnetic coupling) conversion, 90 degrees or -90 degrees phase shift between the adjacent resonators can easily be obtained and works as a key factor in the transformation between different filtering coupler modes. With this simple configuration, the proposed coupler achieves reconfigurable FRC and FBC with not only operating frequency tuning over a wide tuning range but also bandwidth and power division ratios (PDRs) control for each filtering mode. In addition, by imposing open circuit at any two ports, the four-port coupler can be converted to the conventional single-ended two-port BPFs with reconfigurable filter orders of second, third, and fourth. The measured results show that the FRC and FBC can continuously cover the frequency ranges of 1.21-1.67 and 1.2-1.61 GHz with -1-dB bandwidth tuning of 60-120 and 55-110 MHz, respectively. The 3- and 6-dB PDRs have been demonstrated for both filtering coupler modes. In single-ended two-port BPF mode, the frequency tuning ranges are measured of 1.12-1.6, 1.16-1.6, and 1.2-1.61 GHz, respectively, for the proposed two-port second-, third-, and fourth-order BPFs. Measured and simulated results are in good agreement, validating the proposed design method.
Novel Reconfigurable Single-to-Balanced, Power-Dividing, and Single-Ended Filter With Frequency and Bandwidth Control
(2019-02-01)
Zhu, Xu
;
Yang, Tao
;
Chi, Pei-Ling
;
Xu, Ruimin
;
電機工程學系
In this paper, a novel tunable filter with reconfigurable single-to-balanced (SE-BAL), power dividing (PD), and single-to-single-ended (SE) filtering functionalities is proposed, for the first time, without any additional switching circuit. The proposed filter only consists of three stepped-impedance resonators, which are loaded and connected by varactors in between. With a very simple and compact configuration, the proposed filter achieves multiple reconfigurable functionalities between SE-BAL filtering, PD filtering, and conventional SE bandpass filtering. Moreover, the reconfigurable SE-BAL, PD, and SE bandpass filter can not only offer continuously frequency tuning over a wide tuning range but also have independent bandwidth tuning and maintain good phase/amplitude balance in each tuning state. The proposed filter is designed and fabricated with the microstrip line technology; the measured results show that the SE-BAL, PD, and SE filtering functions can be continuously tuned from 1.02 to 1.32, 0.96 to 1.27, and 1 to 1.28 GHz, with 1-dB bandwidth tuning from 30 to 60, 30 to 110, and 70 to 130 MHz, respectively. The amplitude and phase imbalances of the SE-BAL and PD bandpass filter are less than 0.4 dB, 1.3 degrees and 0.5 dB, 1.5 degrees, respectively, in the passband of each tuning state. Good agreement was obtained between simulated and measured results.
Novel Tunable Isolation Network Used in Ring-Type Single-to-Balanced, Power-Dividing, and Single-Ended Filter With Arbitrary Power-Division Ratios
(2020-02-01)
Zhu, Xu
;
Yang, Tao
;
Chi, Pei-Ling
;
Xu, Ruimin
;
電機工程學系
In this article, a novel tunable isolation network and a novel ring-type reconfigurable single-to-balanced (SE-BAL), power-dividing (PD), and single-to-single-ended (SE) bandpass filter is proposed. The tunable isolation network consists of a simple $\pi $ -type resistive network with tunable varactors, while the proposed filter consists of three ring-type stepped impedance resonators (SIRs) connected by varactors in between. By simply combining the proposed tunable isolation network and the proposed ring-type reconfigurable filter, it can achieve multiple reconfigurable functions among SE-BAL filtering, PD filtering, and conventional SE filtering with fully matched three ports, arbitrary power-division ratios (PDRs), high output isolations, and excellent amplitude and phase balance, in addition to continuous frequency and independent bandwidth tuning. The proposed filter is demonstrated using the microstrip line technology. The measured results show that the SE-BAL, PD, and two SE filtering functions can continuously cover the frequency ranges of 1.03-1.61, 1.01-1.53, 1.03-1.56, and 1.06-1.48 GHz with -1-dB bandwidth tuning of 35-80, 50-140, 60-130, and 70-140 MHz, respectively; the 1-, 3-, and 5-dB PDRs have been demonstrated for both SE-BAL and PD filtering modes. The measured output return losses and isolation are better than 19 and 18 dB, respectively, for SE-BAL filtering mode and 20 and 16 dB, respectively, for PD filtering mode. Good agreement is obtained between the simulated and measured results.