Download Adaptive RF Front-Ends for Hand-held Applications by Andre van Bezooijen, Reza Mahmoudi, Arthur H.M. van Roermund PDF

By Andre van Bezooijen, Reza Mahmoudi, Arthur H.M. van Roermund

The RF front-end – antenna blend is an important a part of a cellphone simply because its functionality is particularly correct to the hyperlink caliber among hand-set and mobile community base-stations. The RF front-end functionality suffers from adjustments in working atmosphere, like hand-effects, which are usually unpredictable.

Adaptive RF Front-Ends for hand held Applications offers an research at the impression of fluctuating environmental parameters. on the way to conquer undesired habit varied adaptive keep watch over tools are handled that make RF frond-ends extra resilient: adaptive impedance regulate, and adaptive strength control.

Several adaptive impedance regulate concepts are mentioned, utilizing a priori wisdom on matching community homes, with a purpose to simplify powerful 2-dimensional keep an eye on. A everyday safeguard notion is gifted, in accordance with adaptive strength keep watch over, which improves the ruggedness of an influence amplifier or preserves its linearity less than extremes. It includes over-voltage, over-temperature, and under-voltage protection.

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Example text

Under mismatch, the minimum and maximum collector voltage magnitude are most extreme at a mismatch phase of zero degrees. At zero degrees mismatch the maximum collector voltage magnitude increases with increasing VSWR, whereas the minimum decreases with VSWR. 3 Die Temperature Fluctuation Power amplifier die temperature is important because over-heating potentially causes thermal run-away of the device. Therefore, in this section we derive the operating conditions at which the die temperature is most extreme.

5 that provides a 1-dimensional impedance correction and uses only one variable capacitor. When the work presented in this book started, it was envisioned that adaptively controlled antenna impedance matching networks will gradually evolve from fully hardware implemented stand-alone modules towards tuner modules controlled by more advanced algorithms implemented in the firmware of phones. Going along this evolutionary path, the required technologies [43–52] for the implementation of very linear tunable elements would need to be developed and optimized in parallel.

2 Circuit diagram of a class-AB power amplifier using a bipolar transistor USUP ISUP UCOL ICOL ZLOAD PLOAD UIN PDISS UQ in which Io is the saturation current of the transistor and UT the thermal voltage. The base-emitter voltage consists of two terms: the DC bias voltage UQ, and a sinusoidal signal of excitation with an amplitude AIN. The exponential relationship can be approximated by a Taylor series and the magnitude of the harmonic components can be determined by applying a Fourier transformation [40].

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