Broadband High-Efficiency Power Amplifier With Quasi-Elliptic Low-Pass Response

Abstract

This paper presents a broadband high-efficiency harmonic-tuned power amplifier (PA) with quasi-elliptic low-pass responses. A combination of continuous Class-F −1 and extended continuous Class-F PA modes is employed to significantly expand the design space. A quasi-elliptic low-pass matching network is proposed, which can realize a broadband impedance matching in the predefined optimal impedance region desired by the combination of PA modes. Furthermore, two transmission zeros are generated near the passband, exhibiting high skirt selectivity and providing rapid impedance transition from the passband to the stopband. A wide stopband covering up to the third harmonic is achieved which shows good harmonic suppression. Design procedures of the proposed broadband PA are presented. To verify the proposed methodology, the broadband PA is fabricated and measured. The implemented PA achieves a bandwidth of 145.2% from 0.5 to 3.15 GHz. Over this frequency range, the drain efficiency is measured as 58-74.9% with the output power of greater than 39.03 dBm and a large signal gain ranging from 8.43 to 15.67 dB. A wide stopband is realized from 3.4 to 10 GHz, showing excellent quasi-elliptic low-pass responses. The measured adjacent leakage ratios (ACLRs) using a 20-MHz LTE signal with digital pre-distortion are below −45.06 dBc. INDEX TERMS Broadband power amplifier, filter-integrated power amplifier, harmonic suppression, high efficiency, quasi-elliptic low-pass matching network.

A continuous Class‐EF power amplifier based on the general continuous mode design theory

“…In simulation, the equivalent large signal model in Figure 3A is used. 15 Impedance matching circuits are designed to meet the impedance requirements of the proposed PA. In Figure 3B, microstrip lines TL1 and TL2 are used to compensate for the parasitic parameters of the transistors and to optimize the performance of the PA. 16 In terms of matching networks, the current widely used low-pass matching technique is used, 17 which will not be analyzed in detail again here.…”

“…Based on the continuous impedance space obtained from the theory, the circuit design is carried out with GAN HEMT CGH40010F. In simulation, the equivalent large signal model in Figure 3A is used 15 …”

Design of bandwidth‐enhanced power amplifier based on class‐EF modes

“…Therefore, as an energy-efficient DCto-RF power converters, switch mode Class-E and harmonictuned Class-F PAs have attracted great attention based on the ability of wave-shaping through appropriate harmonic termination. [7][8][9][10][11][12] Nevertheless, although the structure of the Class-E PAs is simple, due to the nonlinear output capacitance of the transistor, the excellent switching behavior is not realized at the gigahertz frequency level, which causes the waveform shaping effect to be unsatisfactory. Meanwhile, for the Class-F PAs, to achieve 100% efficiency, a complex load network is required to realize terminals, leading to bandwidth constraints.…”

“…WITH the rapid evolution of modern communication technology, the radio frequency front‐end systems of the fifth generation (5G) mobile communication require highly efficient power amplifiers (PAs), which can operate multiple signal standards at different frequencies 1‐56 . Therefore, as an energy‐efficient DC‐to‐RF power converters, switch mode Class‐E and harmonic‐tuned Class‐F PAs have attracted great attention based on the ability of wave‐shaping through appropriate harmonic termination 7‐12 . Nevertheless, although the structure of the Class‐E PAs is simple, due to the nonlinear output capacitance of the transistor, the excellent switching behavior is not realized at the gigahertz frequency level, which causes the waveform shaping effect to be unsatisfactory.…”

Design of high‐efficiency continuous resistive‐reactive class‐J power amplifier

“…In order to tailor the requirements of modern communication systems, PAs are moving towards broadband and high‐efficiency. Commonly used high‐efficiency PAs include class‐F −1, 1 class‐F 2‐4 and class‐E 5 . A class‐F PA can achieve 100% efficiency by controlling the odd harmonics open circuit and the even harmonics short circuit, but it cannot maintain high efficiency in broadband.…”