چكيده به لاتين
Power amplifiers are one of the most critical components of telecommunication and military systems that impress the overall performance of the system, such as efficiency, output power, bandwidth, price, and so on. In general, the design of broadband and high-efficiency power amplifier has a significant impact on the overall performance of a telecommunications and military system. In this thesis, we plan to describe the design and construction of a 45-watt microwave amplifier with drain efficiency more than 50% in the frequency band of 0.8-3.3 GHz using the harmonic tuning method. We use the CREE CGH40045 transistor to design this amplifier. At all procedure of the design, we use ADS software, which is a powerful software for designing high-frequency circuits.
The base of this design is using the optimal region, instead of optimum point at each frequency point in the frequency band and out-band harmonic impedances. The main challenge in designing high-efficiency power amplifiers with the bandwidth more than of one octave is the in-band harmonic interference that causes efficiency degradation, so we decide to define these optimal regions to manage output power and efficiency. For designing the broadband impedance matching networks, we set new criteria based on the regions that already defined to put the impedance seen on the drain and gate side of the transistor at each frequency to the corresponding optimal region.
Successful fabrication of a highly efficient 45-W multioctave PA employing these techniques presented to demonstrate the effectiveness of this approach. The output power of more than 45 W obtained with a minimum measured drain efficiency higher than 56% over the 0.8–3.3 GHz band. Besides, the minimum large-signal gain at this frequency band is 8.6 dB.
