Study On Key Technologies Of 3-mm Power Combiner

The power synthetic technology in solid state is widely used in a system of millimeter wave imaging,negative weapons,millimeter wave detection,millimeter wave measuring tools and other fields,which has advantages of high stability,long service life,small size and so on.However,the output power of monolithic solid-state devices is limited,and there is still a certain distance from the requirements of the above application scenarios.Therefore,power synthesis technology is needed to achieve higher output power,and higher output power means higher operating distance and stronger anti-interference ability.Synthesis efficiency,saturated output power and bandwidth are important indicators of power synthesis.Synthetic efficiency,output power and wide band are important parameters for power synthesis.The energy use of the synthesis amplifier depends on the synthesis performance,while output and system width directly determine the device's location of use.In order to achieve high combining efficiency,high output power and wide band,a 24-ways power combining amplifier based on radial waveguide is designed1.The primary factors affecting the synthesis efficiency,saturation output power and stability of power synthesis are analyzed,including amplitude and phase consistency,isolation between ports,loss of three main synthesis modes and overall heat dissipation.Based on the analysis of these indexes,the scheme of combining12-ways power synthesis network and 2-ways power synthesis amplifier is adopted to realize 24-way power synthesis amplifier.2.Considering that the size of W-band coaxial line is too small to be used as the input directly,two kinds of waveguide coaxial transition structures are proposed.After comprehensive consideration,the short-circuit waveguide coaxial transition is selected,and a 12-ways waveguide power divider is designed.The waveguide coaxial transition is fabricated and tested back-to-back.In 88-105 GHz,the return loss of 12 path waveguide back-to-back is more than 15 d B,and the insertion loss is less than 1.2d B.In addition,a coplanar magic T power divider with absorbing material is designed and fabricated.In the whole W-band,the measured results show that the return loss is greater than 19 d B,the single channel loss is less than 0.2d B,and the isolation is greater than 14 d B.3.Using coplanar magic T(absorbing material),14 sets of W-band 2-ways power combining amplifiers are designed and fabricated.The test results show that the average output power of 14 sets of two-way power combining amplifiers is more than 30 d Bm and the average combining efficiency is about 90% at 84-98 GHz.Considering that the24-ways power combining amplifier needs larger driving power,two sets of two channel power combining amplifiers are combined with coplanar magic T(absorbing material)power divider to form four channel power combining amplifiers.The measured results show that the output power of the four channels power combining amplifiers is more than 32 d Bm and the maximum output power is 33.72 d Bm@88GHz The maximum synthesis efficiency is 90.66%@88GHz.4.Two 12-ways waveguide power dividers and 12 sets of 2-ways synthetic amplifiers are combined to form a 24-ways power synthetic amplifier.The measured results show that the output power of the amplifier is higher than 38.8d Bm in84-100 GHz.And the maximum output power is 40.96 d Bm@88GHz,the highest synthesis efficiency is 87.24%@94GHz.