Research And Design Of Monolithic Microwave Hybrid Integrated Power Amplifier

RF power amplifiers(RF PAs)are a major part of wireless transmission systems.Currently,the GaAs process is the primary process for RF power amplifiers.However,the maturity of gallium nitride(GaN)technology provides an opportunity for substantial system level improvements.The high dielectric breakdown field of GaN results in higher voltage operation and hence higher power densities.With the help of GaN,the efficiency and the maximum output power of a microwave radio can be substantially increased—directly impacting the network cost of ownership.Today,GaN monolithic microwave integrated circuits(MMIC)are being introduced in commercial microwave radios.To date,most vendor approaches to applying GaN to power amplifiers have relied on packaging techniques found in earlier generation devices like Si laterally diffused metal-oxide-semiconductors(LDMOS)and Si bipolar junction transistors(BJT).By replacing the silicon material in these packages with GaN,improvements in power density and efficiency have been achieved,but the continued reliance on conventional ceramic packaging,hasn't yielded meaningful reductions in component size or weight.Therefore,this paper proposes a new hybrid integration technology based on GaAs and GaN processes that is miniaturized,light and thin,highly integrated,and low cost.This hybrid integration solution combines the advantages of both GaAs and GaN technologies.In the frequency range of the octave bandwidth of 220 to 520 MHz,the output power of up to 10 W is provided.The hybrid integrated MMIC is packaged in a low cost 10 × 10mm2 LGA surface-mount plastic package,enabling system designers to overcome the challenges of size,weight,performance and cost(SWaP-C)while meeting the system s requirements for broadband,higher power,efficiency and reliability.The research contents and innovation points of this thesis are as follows:1.This paper proposes a hybrid integration technology that is miniaturized,light and thin,highly integrated,and low cost.This technology balances size,weight,performance and cost(SWaP-C)while ensuring power amplifier broadband,high gain,high efficiency,high power,and high linearity.In this paper,high-power devices of different processes are mixed and packaged in one package.Utilizing the new BT substrate material,the chip integrates a GaAs driver amplifier,a GaN power amplifier and internal matching circuits in the LGA package to achieve high integration,high gain,high efficiency,wideband(above an octave)and small size design requirements.By reducing the amount of GaN used and using the plastic packaging method,the overall cost of the chip is greatly reduced,and the cost is reduced by more than 50%.2.The well-known key advantages of GaN compared to GaAs,such as higher power density,higher PAE and wider band capability,accelerates the developments of such semiconductor devices.Therefore,for the above design method,the broadband design of the first-stage GaAs driver amplifier is very important.This paper designs and manufactures a 200-1200MHz wideband,high gain,high power driver stage power amplifier based on a 2?m InGaP/GaAs Heterojunction Bipolar Transistor(HBT)process using a negative feedback technique and a current mirror adaptive linearization bias technique.3.This paper presents a new thermal shunt structure for GaAs HBT devices.By introducing the collector metal,a heat dissipation path from the power source of the power amplifier to the ground is newly added,and the base-collector junction temperature is lowered,the heat distribution of the GaAs power amplifier is optimized,the efficiency is improved,and the reliability of the chip is further improved.4.This paper presents a method to improve the breakdown voltage(BV)of GaAs HBT devices.By increasing the sub-collector layer(N+ Sub Collector region)of the HBT device,the thickness of the epitaxial layer of the collector region is increased,and the doping concentration of the collector layer is lowered to increase the breakdown voltage of the device.The breakdown voltage of GaAs HBT devices is increased from 14V to 19V.5.Based on the 0.25?m SiC-based GaN HEMT process,the final stage power amplifier is designed and fabricated.GaAs driver stage power amplifier and GaN power amplifier are the main part of monolithic microwave integrated power amplifiers.Their bandwidth,power,efficiency and other properties ultimately determine the performance of the power amplifier.6.This paper presents a new BT substrate structure.For many years,high power amplifier packages have been dominated by metal and ceramic packaging processes,and GaN is no exception.However,this approach and continued reliance on conventional ceramic packaging does not significantly reduce component size or weight.Plastic packaging can reduce the size and weight of components,but the power consumption of the device is higher.This paper addresses thermal design challenges by placing thermally concentrated GaAs MMIC and GaN transistors on top of a high thermal conductivity copper filled via array to overcome thermal defects in plastic packages.And enable high-power GaN devices to operate with good performance and high reliability in plastic packages.7.This paper also proposes a new Darlington ESD/EMP protection circuit with ultra-low load capacitance(less than 0.1 pF).GaAs and GaN MMICs are very sensitive to electrostatic discharge(ESD)and electromagnetic pulse radiation(EMP).With the application of various advanced electronic devices in modern military weapons and wartime communication systems,they are also increasingly threatened by strong electromagnetic pulse interference.In RF systems,traditional EMP protection methods include transient voltage suppression(TVS)diode or metal oxide varistor(MOV),etc.Although they provide adequate EMP protection,parasitic capacitance of traditional protection devices will cause degradation of RF system performance.A new darlington ESD/EMP protection circuit with ultra-low load capacitance(less than 0.1pf)provides ESD/EMP protection without degrading RF circuit performance.The chip is designed and manufactured with 2?m InGaP/GaAs HBT process,which is conducive to the integration of the chip to further improve the reliability of the MMIC chip.