Millimeter Wave Solid State Power Synthesis Technology Research

With the application field of the millimeter-wave technology expanding, the power requirement of the millimeter-wave transmitter is continuously improved. The millimeter-wave power amplifier is the indispensably key component of the millimeter-wave transmitter. But the output power of a single solid power amplifier is limited, so the power combining technology which can combine the output power of several solid power amplifiers is demanded to meet application requirement.This paper presents a novel waveguide E-T junction after deeply studying power dividers for example3dB directional coupler, waveguide Magic-T, waveguide E-T junction,etc. The structure can solve the problem of traditional T-junction waveguide’s low isolation and unmatched three ports through inserting the thin film resisitive septum on the branch place of T-junction waveguide. On the basis of the novel waveguide E-T junction, this paper designs a four-way binary-tree power dividing/combining network. Then, we fabricate a four-way power combining amplifier through choosing NC1188C-3436high-power MMIC chip (its output power is better than1W) as the power amplifier chip:a MMIC chip is separately put into a waveguide-microsrip transition cavity to form a power amplifier module, so every MMIC chip possesses the separate heat dissipation space. Then, we place four power amplifier modules on power dividing/combining network side by side to complete the fabrication of the four-way power combining amplifier. The power combining amplifier has advantages of easy installation, easy maintenance and good heat dissipation.The measured results show that the saturated output power of the four-way power combining amplifier is more than35dBm and the power-combining efficiency is more than80%in34-36GHz. And the power combining amplifier can obtain the maximum saturated output power of36.08dBm(4.06W) at35GHz, the maximum power-combining efficiency of94.4%at35.2GHz.