RF-MEMS based adaptive antenna matching module

Abstract

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On the Trade-Off Between Quality Factor and Tuning Ratio in Tunable High-Frequency Capacitors

“…Switches can also be connected in series for higher breakdown voltage, but normally at the cost of additional parasitics. Power handling from, e.g., a 3 V battery can be increased with voltage converters (see, e.g., [50]). However, a low operation voltage will lower the cost and size and will make the device more attractive for certain applications.…”

An Automatic Antenna Tuning System Using Only RF Signal Amplitudes

“…RF front ends are typically designed under the assumption of a 50 Ω antenna impedance, for which maximum efficiency, talk-time, quality of the link, and maximum life-time are obtained. Due to detuning of the narrow band antenna, significant degraded efficiency and life-time can be observed [2]- [4]. This paper presents an automatic antenna tuner system that can tune fluctuations in antenna impedances, resulting in higher (overall) efficiency and lower demands on robustness aspects for front end RF blocks.…”

“…Note that by using an automatic tuner, the bulky and expensive isolators that are widely applied to absorb reflected power become redundant [4].…”

Thin fim barium strontium titanate capacitors for tunable RF frond-end applications

“…Switches can also be connected in series for higher breakdown voltage, but normally at the cost of additional parasitics. Power handling from, e.g., a 3 V dc battery can be increased with voltage converters (see, e.g., [71]). However, a low operation voltage lowers the cost and size, and makes the device more attractive for an application.…”

“…To eliminate the imaginary part of the load, to obtain the characteristic impedance of 50 Ω, the matching network should have an output impedance which equals the conjugate of the antenna impedance. Tunable capacitors can re-tune the circuits impedance towards or to the characteristic impedance Z 0 [71,171].…”