Browsing by Author "Chien, Chun-Pin"

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A Tunable Balanced Coupler With Improved Phase Balance and Extended Bandwidth
(2019-01-01)
Chi, Pei-Ling
;
Lin, Hong-Min
;
Chien, Chun-Pin
;
電機工程學系
;
Department of Electrical and Computer Engineering
This paper proposes a balanced coupler with improved phase balance and extended bandwidth for a wide range of tunable power-dividing ratios. This differential coupler uses only two varactors and can demonstrate tunable power-dividing ratio and quadrature phase difference between outputs with theoretically perfect differential-mode return loss and port isolation, and complete common-mode suppression. The coupler analysis, design equations/graph, and parametric study will be given in detail. As a proof-of-concept, a microstrip prototype operating at 1 GHz was fabricated. Measured results show that the power-dividing ratio can be tuned from -5.5 dB to 11.9 dB at the center frequency where the insertion loss is less than 0.84 dB, the phase imbalance and isolation between differential outputs are less than 3.9 degrees and greater than 23.2 dB, respectively. Moreover, the differential-mode return loss and the common-mode rejection are greater than 27.5 dB and 35.2 dB, respectively. Measured and simulated results are in good agreement.
Balanced-to-Balanced Power Divider with Tunable In-Phase/Out-of-Phase Power-Dividing Ratio
(2018-01-01)
Chi, Pei-Ling
;
Chien, Chun-Pin
;
電機工程學系
;
Department of Electrical and Computer Engineering
This paper presents a balanced-to-balanced microstrip power divider with a wide range of continuously tunable power-dividing ratios for either in-phase or out-of-phase outputs. Based on simple design equations, the proposed power divider can theoretically attain ideal mixed-mode responses, including the in-phase and out-of-phase designs, for an arbitrary power ratio by a proper control of the used varactor capacitances. A single-layer power divider was prototyped and measured. Given the differential-mode return loss and output isolation greater than 15 dB, the power-dividing ratio was tuned from 11.1 dB to 24.2 dB and from 1.3 dB to 21.1 dB for the in-phase and out-of-phase outputs, respectively. For all states, the common-mode suppression achieved greater than 63.9 dB at the center frequency.