January 14, 2018

Thermal memory effect characterization of GaN based class ABJ power amplifier using intrinsic temperature measurement

Enhancing power efficiency and bandwidth of RF power amplifiers (PAs) is always a challenge for future mobile basestation transceivers. Static and especially dynamic nonlinear effects are mainly responsible for decreasing before mentioned parameters. Static effects can be usually characterized by measuring the PA output with a defined input signal. Fast changing dynamic nonlinearities like thermal memory effects are more difficult to determine but have a strong influence on the transfer characteristic of the PA. This work shows a method to measure the temperature of the device close to its channel in RF operation of the PA.

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Recent Publications

January 01, 2018

Fair Dynamic Spectrum Management for QRD-Based Precoding with User Encoding Ordering in Downstream G.fast Transmission

In next generation DSL networks such as G.fast, employing discrete multi-tone transmission in high frequencies up to 212 MHz, the crosstalk among lines reaches very high levels. To precompensate the crosstalk in downstream transmission, QRD-based precoding has been proposed as a near-optimal dynamic spectrum management (DSM) technique. However, the performance ...

January 01, 2018

Practical Mitigation of Passive Intermodulation in Microstrip Circuits

This paper presents new experimental evidence and a novel practical approach for mitigation of passive intermodulation (PIM) in microstrip circuits fabricated on commercial printed circuit board laminates. The mechanisms of distributed PIM in microstrip circuits are reviewed and a phenomenology of PIM generation due to locally enhanced electromagnetic fields at ...

January 01, 2018

Efficient Cooperative HARQ for Multi-Source Multi-Relay Wireless Networks

In this paper, we compare the performance of three different cooperative Hybrid Automatic Repeat reQuest (HARQ) protocols for slow-fading half-duplex orthogonal multiple access multiple relay channel. Channel State Information (CSI) is available at the receiving side of each link only. Time Division Multiplexing is assumed, where each orthogonal transmission occurs ...