비대칭 소자와 Out-Phased Current Combining 방식을 사용한 광대역 Doherty 전력증폭기 (Broadband Doherty Power Amplifier Using Out-Phased Current Combining Method and Asymmetric Cells)

서지정보

· 발행기관 : 한국전자파학회
· 수록지 정보 : 한국전자파학회 논문지 / 35권 / 11호 / 868 ~ 879페이지
· 저자명 : 송재성, 배순철, 빈수현, 양영구

초록

본논문에서는OCC(out-phased current combining) 방식과 비대칭 구조의 셀을 사용하여 DPA(Doherty power amplifier)의OBO(output power back-off)를 8 dB로 확장하고 광대역 특성을 갖는 DPA의 구조를 제시한다. 제안된 DPA의 정합 조건을정의하기위해전송선로를이용해OMN(output matching network)이 분석되었다. 광대역 DPA 설계를 위해 추가적인 방법을 사용한기존논문들과달리전송선로기반OMN이기생성분이포함된집중수동소자기반OMN으로변환될때나올수있는여러구조중대역적으로우수한OMN 구조를채택하였다. 제작된DPA는3.0∼4.2 GHz 대역에서CW 신호를이용하여측정한결과, 최대출력전력42.0∼43.4 dBm에서55.1∼65. 9 %의 DE(drain efficiency)을 얻었고 8 dB OBO 영역에서전력이득6.6∼10.8 dB, 43.1∼53.7 %의 DE를 얻었다. 또한 100 MHz의 대역폭과 7.8 dB의 PAPR(peak-to-average power ratio)를 갖는 5G NR 신호로 측정한 결과 평균전력 34.0∼35.4 dBm에서 45∼55 %의 DE와 −34.3∼−23.2 dBc의ACLR(adjacent channel leakage power ratio)을 얻었다.

영어초록

In this paper, we propose a broadband structure for a Doherty power amplifier (DPA) with an extended output power backoff (OBO) of 8 dB by using an out-phased current combining (OCC) method and an asymmetric architecture. To determine the matching conditions of the proposed DPA, the output matching network (OMN) is analyzed using transmission lines. Previous studies have employed additional circuits for broadband DPA design; in contrast, this paper presents the use of a compact but optimal OMN structure that provides a broad bandwidth. This structure is selected following the conversion of the transmission line-based OMN into lumped element-based OMN, incorporating the parasitic components of the transistor. The fabricated DPA with the proposed broadband OMN exhibits a drain efficiency (DE) of 55.1∼65.9 % at the output power of 42.0∼43.4 dBm across the 3.0∼4.2 GHz band. For the OBO of 8 dB, power gain of 6.6∼10.8 dB and DE of 43.1∼53.7 % are achieved by using a continuous wave (CW) signal. Additionally, by using a 5G New Radio (NR) signal (100 MHz bandwidth and 7.8 dB PAPR), the amplifier archives a DE of 45∼55 % at 34.0∼35.4 dBm output power, with an adjacent channel leakage power ratio (ACLR) ranging from −34.3 to −23.2 dBc.

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