Adaptive Multi-Band Multi-Mode Power Amplifier Using Integrated Varactor-Based Tunable Matching Networks

A Design of Adaptive Impedance Tuning Circuit for UHF-Band Using λ/4 Transmission Line and π-Network

“…임의의 부하단 임피던스를 측정하기 위한 부정합 측정부는 방향성 결합기 [5]～ [7] 를 이용하여 신호의 크 기만을 측정하는 방법과, RF 검파기(detector) [1], [8]～ [10] 나 로그 증폭기(logarithmic amplifier) [11] [7] . [15] , 이러한 방법으로 넓은 임피던스 가변 대역을 만족시키기 위해서는 많은 갯 수로 이루어진 PIN 다이오드 열(bank)과 각각의 PIN 다이오드의 on/off를 수행하여야 하므로 적응형 임피 던스 정합 회로의 조정 알고리즘이 복잡해지는 단점 이 발생하게 된다.…”

An Efficient Adaptive Antenna-Impedance Tuning Unit Designed for Wireless Pacemaker Telemetry

“…To address the problem due to impedance mismatch, many antenna impedance tuning units operating iteratively and/or using directional coupler to evaluate the quality of the link were investigated [7][8][9][10][11][12][13][14][15]. Since the use of a bulky additional coupler into the device is totally inacceptable and since iterative matching process spends time and consumes power to set the proper state of the network, we investigate on a novel coupler less method [25] solving the problems related to the impedance mismatch in a single iteration.…”

“…Most of existing antenna-impedance tuning units [7][8][9][10][11][12][13][14][15] operates iteratively to successfully adapt source and load impedances. However, iterative methods generally spend several hundred milliseconds to calibrate the system and are not well suited to low power pacemaker applications where energy is lost during the calibration as the proper state configuration of the system is not yet obtained.…”

From device characterization to system level analysis of dual band PA design in SiGe technology

“…2) makes use of tunable/switching components in the matching networks, to enable the capability to cope with more than one standard. This solution, usually referred as Dual Band SiGe PA Designadaptive PA, is also adopted in the case of efficiency enhancement as in [4], selecting the proper termination for each power level.…”

“…Changing simultaneously inductors and capacitors values, the loading conditions can be varied, while keeping constant the phase delay, which is of mandatory importance in digitally modulated systems [4]. Although in principle very flexible and suitable for the implementation of software-based controlled subsystems, the losses exhibited by the tunable components represent a critical drawbacks.…”