Miniaturized Dual-Band Matching Technique Based on Coupled-Line Transformer for Dual-Band Power Amplifiers Design

Abstract

Abstract-This study presents a novel miniaturized dual-band coupled-line impedance transformer.This dual-band matching technique uses the characteristics of coupled-line and dual-band stubs to realize matching arbitrary complex impedance to arbitrary complex impedance at two arbitrary uncorrelated frequencies. Especially, it satisfies the demand of dual-band matching at two relatively closed operating frequencies (n = f 2 /f 1 ≤ 1.2), and occupy a very small circuit area with inherent DC-Block function. The proposed synthesis approach is validated by the design and fabrication of a 30 W gallium nitride (GaN)-based class-AB power amplifier (PA) for GSM and WCDMA at 1800 MHz and 2140 MHz. The PA's output matching network based on the proposed structure can accurately match 50 Ω to the ideal load impedances of the transistor at two designed frequency simultaneously and has 20% and 15% bandwidth for which the reflection coefficient magnitudes are less than 0.1, respectively.

A Novel Compact Dual-Frequency Coupled-Line Transformer With Simple Analytical Design Equations for Frequency-Dependent Complex Load Impedance

“…Impedance transformers, namely, matching networks are important and fundamental circuit cells in several microwave components (devices) and systems [1][2][3][4][5][6]. For example, impedance transformers are main parts of various power dividers and combiners.…”

A T-Section Dual-Band Matching Network for Frequency-Dependent Complex Loads Incorporating Coupled Line With Dc-Block Property Suitable for Dual-Band Transistor Amplifiers

“…It may be noted that since there is no standard definition for a frequency-dependent complex load; different reported designs have used different frequency dependency of load, thus it won't be fair to make comparison based on the bandwidth [28]. Moreover, the design reported in [25] also provides DC-blocking, but works for a very limited range of r.…”

“…Usually lumped component based matching networks [22] are simpler, but fabrication of lumped component is difficult at higher frequencies and maintaining their value over a wide frequency range is extremely difficult [23]. Furthermore, few coupled line based dual-band impedance transformers exhibiting good performance have been reported and in general they may or may not provide inherently DC blocking [24][25][26].…”

Dual Fed Distributed Amplifier With Controlled Termination Adjustment

“…In [22,23] is shown the narrow frequency UHF band that demonstrated high efficiency employing switched gain stage and class E approaches, respectively with 7.2 V. Other recent works related to high performance power amplifier are reported in [24,25] with GaAs HBT and CMOS technology, respectively. In the other hands, power amplifier design with parallel-coupled transformer matching is demonstrated in [26,27].…”