Dual‐Wideband Filtering Power Amplifier With Elliptic Passbands via Extracted‐Pole Matching Filters

This paper explores a dual‐wideband extracted‐pole matching filter (EPMF) designed to facilitate a highly selective dual‐wideband filtering response for power amplifiers (PAs). By employing the EPMF, the PA aims to achieve two 3‐pole elliptic responses, potentially enhancing the overall filtering shape and bandwidth efficiency. A systematic synthesis technique and physical realization method of the EPMF, specifically tailored for PA applications, are discussed. A proof‐of‐concept class‐AB PA operating at 1.5–1.7 and 1.9–2.1 GHz is evaluated, exhibiting a steady dual‐band elliptic response with an in‐band flatness of 1.12 dB, showing close consistency with the theoretical analysis. The measured peak saturation power () reaches 41.0 dBm, which is primarily attributed to the optimized harmonic terminations and out‐of‐band suppression provided by the EPMF network. Under continuous‐wave (CW) excitation, the peak power‐added efficiency (PAE) ranges from 61%–63% and 68%–71%. Furthermore, when evaluated with 18‐MHz LTE signals, the PA maintains ACPRs below −34/−36 dBc at backed‐off average power levels, indicating favorable inherent linearity without the need for digital predistortion (DPD).