Browsing by Author "Li, Jian-Yu"

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Design of Doherty Power Amplifier for Carrier-Aggregation in LTE-A Small Cell Base Station
(2016-01-01)
Li, Jian-Yu
;
Hsu, Yu-Cheng
;
Wu, Lin-Kun
;
電信工程研究所
;
Institute of Communications Engineering
The demand for higher data rate has led to the utilization of carrier aggregation technique, where the linearity and efficiency requirements of power amplifier become more stringent especially for base station. To improve efficiency around the average output power, the two-way symmetrical Doherty power amplifier with unequal input power splitting ratio is proposed. The experimental results show that the proposed Doherty architecture delivers a 39 dBm average output power with low error vector magnitude and high efficiency. Finally, an example of two LTE-Advanced component carriers (CCs) at Band 41 is used to verify the feasibility of the proposed Doherty concept in intra-band carrier aggregation.
High Reliable Doherty Power Amplifier Module for LTE Small Cell Base Station
(2017-01-01)
Hsu, Yu-Cheng
;
Li, Jian-Yu
;
Wu, Lin-Kun
;
電信工程研究所
;
Institute of Communications Engineering
The small-cell base station requires a high linearity, high reliable and high efficiency power amplifier to enhance signal strength in a coverage region. To meet the demand, the 2.6 GHz two-way symmetrical Doherty power amplifier module which uses modularized components, enhances system stability and integrates with heat sink is proposed. The experimental results show that the proposed module delivers a power-added efficiency of 27%, a gain of 47 dB, and adjacent channel leakage ratio of below -33 dBc at an average power of 40 dBm without non-linearity compensation for the LTE signal. Finally, the model of AM-AM and AM-PM with memory effects are predicted by measurement results and it can be used to improve the linearity of the proposed power amplifier.
Miniaturized Hybrid Ring Bandpass Filter with a Notched Band and an Improved Upper Stopband Using Double-Sided Parallel-Strip Lines
(2012)
Li, Jian-Yu
;
Chi, Chun-Hsiang
;
Chang, Chi-Yang
;
電信工程研究所
;
Institute of Communications Engineering
A wideband stepped-impedance hybrid bandpass filter with a notched band and an improved upper stopband is proposed. The double-sided parallel-strip line (DSPSL) is employed to implement the proposed filter. The stepped-impedance structure improves the upper stopband performance and reduces the size. Besides, the open-circuited stub embedded in the stepped-impedance line of the hybrid ring is used to create a notched band. The low impedance portion of the stepped-impedance line is formed by the DSPSL while the high impedance portion of that is constructed by the offset double-sided parallel-strip line (ODSPSL). The design example is fabricated on a 20 mil RO4003 substrate. The measurement results show excellent agreements with the electromagnetic simulation.
Synthesis and Design of Generalized Chebyshev Wideband Hybrid Ring Based Bandpass Filters With a Controllable Transmission Zero Pair
(2010-12-01)
Li, Jian-Yu
;
Chi, Chun-Hsiang
;
Chang, Chi-Yang
;
電信工程研究所
;
Institute of Communications Engineering
A systematic and analytical method for the exact synthesis of generalized Chebyshev wideband hybrid ring based bandpass filters with a controllable transmission zero pair is developed in this paper. The basic configuration of the proposed filters consists of a hybrid ring, a multi-section short-circuited stub and a multi-section open-circuit stub. In this configuration, the position of the controllable transmission zero pair can be easily designed by setting the impedances of the multi-section short-circuited stub and the multi-section open-circuit stub. According to the position of the controllable transmission zero pair, two kinds of filters are proposed. The filter has a controllable transmission zero pair on the real axis (imaginary frequency) that they can be arranged to improve the group delay flatness. On the other hand, the filter has a controllable transmission zero pair on the imaginary axis (real frequency) and the desired stopband suppression can be obtained by adjusting the optimal position of them. This synthesis method is developed to obtain the impedance value of each line section and ripple factors of the filters with respect to given specifications (center frequency, passband bandwidth and transmission zeros). Two design examples, the fifth-order filter with a controllable imaginary frequency transmission zero pair and the fifth-order filter with a controllable real frequency transmission zero pair, are synthesized and fabricated. The measured results validate and confirm the theoretical predictions.
Synthesis of Wideband Bandpass Filters Using a Hybrid Ring Shunts with an Open-circuited Stub
(2011)
Li, Jian-Yu
;
Chi, Chun-Hsiang
;
Chang, Chi-Yang
;
電信工程研究所
;
Institute of Communications Engineering
Wideband bandpass filters using a hybrid ring with a shunt open-circuited stub is proposed and developed. The impedances of the hybrid ring and open-circuited stub determine the location of the transmission zero pair in the bandpass domain. This controllable transmission zero pair can be designed to flatten the group delay or improve the selectivity of the filter. Two experimental filters using the same circuit topology are realized to verify the improvement of group delay flatness and selectivity respectively. These two design examples are implemented by balanced microstrip line on a 20-mil RO4003 substrate. The measurement results show excellent agreements with the electromagnetic simulation.
Tri-Band and Quad-Band Filter Design Using E-Shaped Resonators
(2011)
Kuo, Yi-Ting
;
Li, Jian-Yu
;
Cheng, Shi-Yu
;
Chang, Chi-Yang
;
電信工程研究所
The semi-analytic procedure is provided for triband and quad-band filter design based on E-shaped resonators. With analytic synthesized procedure in dual-band filter design and connect two filters using double-diplexing configuration, the tri-band and quad-band performances can be achieved. The simulated results for the synthesized filters agree well with the ideal performances after some fine tuning. Two microstrip implementations are provided to demonstrate the reliability of tri-band and quad-band filter design.