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.
IEEE Transactions on Microwave Theory and Techniques