Now showing 1 - 2 of 2
  • Publication
    Highly Efficient Broadband Continuous Inverse Class-F Power Amplifier Design Using Modified Elliptic Low-Pass Filtering Matching Network
    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 34.5 dBm, the proposed PA, combined with digital pre-distortion, achieved adjacent channel leakage ratios (ACLRs) below −45 dBc, with average efficiency (AE) ranging from 37% to 45.8%. Similar performance is measured when the proposed PA is driven by a dual-band dual-mode modulated signal with a 100-MHz instantaneous bandwidth at a center frequency of 2.14 GHz.
    Scopus© Citations 115  889
  • Publication
    A Broadband High-Efficiency Doherty Power Amplifier with Integrated Compensating Reactance
    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). When driven by a 20-MHz long term evolution modulated signal at 6.5-dB back-off power, the DPA can achieve an average efficiency of more than 50% with high linearity after linearization over the design frequency band.
    Scopus© Citations 113  812