Dual-Band High-Efficiency Power Amplifier With Adjustable Transmission Zero

Dual-Band Continuous Class-F−1 Power Amplifier With Second-Harmonic Suppression for Harmonic Radar Systems

“…A power amplifier (PA) is a crucial circuit in wide-band or multiband harmonic radar systems that amplifies the fundamental radar signal while suppressing the harmonic signals at different frequencies. Various PA topologies, including three-path [5], dual-band impedance rotation [6], transformers [7], various classes of PA operations [8]- [12], and adjustable transmission zero [13], have been proposed to achieve high efficiency with bandwidth expansion. However, previous studies have demonstrated harmonic suppression characteristics in wide or multiple bands.…”

Compact dual‐frequency impedance transformer for frequency‐dependent complex source and load

“…In addition to traditional communication systems, impedance transformers are used in wireless power transfer systems for power transfer efficiency improvement. Impedance transformers [1][2][3][4][5][6][7][8][9][10][11][12] consisting of only transmission lines require no lumped element resulting in low cost and low parasitic effect, but the resulting circuit area is large. By contrast, impedance transformers consisting of only lumped elements [13][14][15][16][17] are compact, but they require particular component values that may be unavailable commercially.…”

“…The aforementioned studies on dual-band impedance transformers have considered a load with real or complex impedances that should be matched to a source with real impedances, typically 50 Ω. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] A more general impedance transformer can match complex impedance loads to complex impedance sources; a typical example for this is the interstage between two transistors in a cascade amplifier.…”

Dual band power amplifier with adjustable transmission zeros based on the parallel and series two section transmission line

“…As one of the most important devices, the PA has been received increasing attention for their performance such as output power, efficiency, bandwidth, etc. Common design techniques for DB PA include reconfigurable devices [3,4,5,6], DB IMN approaches [7,8,9,10,11,12,13,14] and real frequency techniques [15,16,17]. As the most developed approach, DB IMN enables efficient operation by transforming the required frequency-dependent complex load impedance at two arbitrary frequencies to the term impedance.…”

“…A DB IMN with insertion of an adjustable TZ was introduced in [11]. Based on this method, an DB PA with an adjustable TZ was designed [10]. However, this article lacked a discussion on the matching bandwidth, its matching bandwidth seemed relatively narrow and could not meet the requirements of most applications.…”