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Limited By:	Author = Xia, Jing;

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A 1.8–2.3 GHz broadband Doherty power amplifier with a minimized impedance transformation ratio (2019)

Yang, Mengsu; Xia, Jing; Zhu, Anding

A 1.8–2.3 GHz broadband Doherty power amplifier with a minimized impedance transformation ratio (2019)

Yang, Mengsu; Xia, Jing; Zhu, Anding

Abstract:

The 2015 Asia-Pacific Microwave Conference (APMC), Nanjing, China, 6-9 December 2015
In this paper, the design and measurement results of a 1.8 GHz to 2.3 GHz broadband Doherty power amplifier (DPA) are reported. A modified load modulation network is designed to minimize impedance transformation ratio over the entire dynamic range for the purpose of extending the operating bandwidth. Experimental results show that the drain efficiency of the proposed DPA maintains above 50% and 63% with continuous wave input signal powers of 26 dBm and 34 dBm, respectively, from 1.8 GHz to 2.3 GHz. When stimulated by a 60-MHz, 12- carrier UMTS signal at 2.14 GHz, the proposed DPA achieved an average efficiency of 53% at 7.6 dB back-off, while the corresponding adjacent channel leakage ratio is linearized to -48.4 dBc with digital predistortion.
Science Foundation Ireland
China Scholarship Council

http://hdl.handle.net/10197/10243

Marked Mark

A Broadband High-Efficiency Doherty Power Amplifier with Integrated Compensating Reactance (2017)

Xia, Jing; Yang, Mengsu; Guo, Yan; Zhu, Anding

A Broadband High-Efficiency Doherty Power Amplifier with Integrated Compensating Reactance (2017)

Xia, Jing; Yang, Mengsu; Guo, Yan; Zhu, Anding

Abstract:

This paper presents a high-efficiency gallium nitride Doherty power amplifier (DPA) using an integrated compensating reactance (CR) for broadband operation. With an additional quarter-wavelength transmission line integrated in the peaking amplifier output, a CR is generated to compensate the load impedance of the carrier amplifier in the low-power region and thus enhance the back-off efficiency over a wide frequency range without affecting the Doherty load modulation at saturation. For this purpose, a peaking output matching network (OMN) is employed to convert the output impedance of the peaking device into quasi-short circuit when it is off and achieve proper impedance matching when it is on. A two-point matching technique using the transmission (ABCD) matrix is employed to design such desired OMN. Measurement results show that the DPA has a 6-dB back-off efficiency of 50%-55% and a saturated efficiency of 57%-71% over the frequency band of 1.7-2.8 GHz (49% fractional bandwidth). ...

http://hdl.handle.net/10197/8390

Marked Mark

Highly Efficient Broadband Continuous Inverse Class-F Power Amplifier Design Using Modified Elliptic Low-Pass Filtering Matching Network (2017)

Yang, Mengsu; Xia, Jing; Guo, Yan; Zhu, Anding

Highly Efficient Broadband Continuous Inverse Class-F Power Amplifier Design Using Modified Elliptic Low-Pass Filtering Matching Network (2017)

Yang, Mengsu; Xia, Jing; Guo, Yan; Zhu, Anding

Abstract:

This paper proposes a design approach for a broadband and high-efficiency continuous inverse Class-F (CCF−1) power amplifier (PA) based on a modified elliptic low-pass filtering (LPF) matching network (MN). From theoretical and practical perspectives, the importance of a swift impedance transition from the higher end of the fundamental frequency band to the lower end of the second harmonic band is discussed, when designing a broadband single-mode PA. After being compared with widely used Chebyshev LPF MNs, a modified elliptic LPF MN, which provides a sharp roll-off, is utilized to provide the required rapid transition. A step-by-step design procedure of the proposed modified elliptic LPF MN is presented. Experimental results show that a high-efficiency CCF−1 PA is realized from 1.35 to 2.5 GHz (fractional bandwidth = 60%) with measured drain efficiency of 68%–82% and output power of 41.1–42.5 dBm. When stimulated by a 20-MHz LTE signal with an average output power of approximately 3...

http://hdl.handle.net/10197/8388

Marked Mark

Improved Doherty Amplifier Design with Minimum Phase Delay in Output Matching Network for Wideband Application (2017)

Xia, Jing; Yang, Mengsu; Zhu, Anding

Improved Doherty Amplifier Design with Minimum Phase Delay in Output Matching Network for Wideband Application (2017)

Xia, Jing; Yang, Mengsu; Zhu, Anding

Abstract:

This letter presents an improved Doherty power amplifier (DPA) for high-efficiency and wideband operations. To achieve the impedance transformations both in the low power region and at saturation, a design approach is proposed to determine the desired minimum phase delays of the carrier and peaking output matching networks, which can simplify the load modulation network of the DPA and extend the bandwidth. For verification, a 1.6-2.2 GHz asymmetric DPA was designed and measured. The designed DPA can deliver an efficiency of 51%-55% at 10 dB back-off power over the whole band. For a 20 MHz LTE signal, an average efficiency of higher than 50% can be achieved at 36 dBm average output power with the linearity of -48 dBc after linearization across the band.
Science Foundation Ireland
Natural Science Foundation of Jiangsu Province of China

http://hdl.handle.net/10197/8400

Marked Mark

Single-Model Single-Feedback Digital Predistortion for Concurrent Multi-band Wireless Transmitters (2017)

Yu, Chao; Xia, Jing; Zhu, Xiao-Wei; Zhu, Anding

Single-Model Single-Feedback Digital Predistortion for Concurrent Multi-band Wireless Transmitters (2017)

Yu, Chao; Xia, Jing; Zhu, Xiao-Wei; Zhu, Anding

Abstract:

In this paper, a novel single-model single-feedback digital predistortion (DPD) technique is proposed to linearize concurrent multi-band wireless transmitters. By employing carrier relocation and band-limiting functions in digital signal processing, DPD model complexity is significantly reduced and only one narrowband feedback loop is required for data acquisition. In the new system, the linearization bandwidth can be arbitrarily reconfigured, which provides considerable flexibility for DPD system design in wideband concurrent operations. Experimental tests were conducted to validate various cases including a concurrent quad-band scenario that is reported for the first time to date. Excellent performance demonstrates that the proposed approach provides an effective solution for reducing DPD system implementation complexity and cost in both digital and analog domains for future wideband concurrent multi-band transmitters.
Science Foundation Ireland

http://hdl.handle.net/10197/8401

Displaying Results 1 - 5 of 5 on page 1 of 1