Research On The Design Technique Of S-band Balanced Power Amplifier Incorporating With GaN HEMT

Power amplifier is the important part of various microwave transceivers.Power amplifiers design technique incorporating with GaN transistors has been attracting continuous interests in the modern microwave engineering field.Compared with general amplifiers,Balanced PAs has broad band and higher power delivering capability.In this article,the design technique of broad band balanced PA is deeply researched.Matching networks is very important in PA design.We need broad band Matching networks to satisfy the need of broad band PAs.Three kind of broad band matching network is theory analyzed and EM simulated.After that,their applicability and reliability are summarized.Power divider or coupler which is also important in balanced PA design is researched,too.Several kinds of common used power dividers and couplers are simulated and their band characteristics are compared with each other.To decrease the size of the branch line 3dB bridge,CMRC structure is introduced and simulated,and a compact 3dB bridge incorporating with CMRC is designed and tested.A broad band power amplifier is designed incorporating with lossy matching networks and balanced structure.The tested result indicate excellent broad band performance.In the frequency range 2.5-3.5GHz,the amplifier exhibits a power gain of 15 dB and the gain fluctuation is lower than ?0.69 dB under small signal condition.The saturated output power reaches 46.8dBm.Which is better than the performance of the power amplifier presented in the datasheet of the transistor.