S-bandında çalışan iki paralel güç yükselticili ve faz kaydırıcılı bir güç birleştirici sistem tasarımı

RF power amplifiers are important blocks in a wireless communication systemthat play a vital role in determining the level of overall performance. In somesituations, more power than a single power amplifier can alone provide is requiredin applications such as a radar or a space communication system. In such cases,power combiners that can surpass the maximum output power level of a singlepower amplifier should be used. In this thesis, we study the performance of apower combiner built in classical binary structure. The combiner operates at3 GHz (S-band) and comprises two power amplifiers which can supply up to38 dBm of saturated power. Wilkinson power dividers/combiners are utilizedat the input/output respectively in order to divide and combine the input andoutput signals. While building a power combiner, one should also note thatthe phases of the amplified signals should be matched at the output or else thelevel of combining loss can reach significant levels. At a phase difference of 180 degrees,the signals will be completely out of phase and will combine destructively atthe output. Therefore, in our study, in order to be able to control the phasesat each arm of the power combiner, two tunable microwave phase shifters areplaced before the active devices. The phase shift generated by these shifters arecontrolled via voltage, hence a desired level of phase shift can be obtained. Bythis, we demonstrate that phase shifters are also important structures for a powercombiner that are instrumental in accomplishing a phase balance between the twoarms. The idea behind the work displayed here can be extended to applicationsrequiring much higher power levels or operating at higher frequencies.