Ka Band Pulse Transmitter Technology Research

The frequency band that is now hotly researching in military electronic area is the millimeter wave (MMW) band. The high power amplifier is one of the critical components of the MMW transmitter. Power combining technology is one of the approaches that can effectively improve the output power. Taking advantage of high power combining efficiency, this paper emphsizes the binary power combining method, including structure design, simulation and measurement.Based on the property of3-port netwoeks, this paper firstly analyzes the commonly used power splitting structures, such as branch waveguide coupler, septum combiner and waveguide to microstrip probes, and then proposed a power splitting/combining structure based on the branch waveguide coupler and waveguide to microstrip probes. This structure has the following characteristics:symmetric structure, balanced power splitting ratio. Therefore, the two critical problems in power combining are solved:placing multiple components in a small room, the balance of amplitude and phase in power splitting and combining.A20W pulse transmitter is designed and tested, when the pulse repeat period is5u s and pulse width is500ns, measurement results show that the rise time and fall time of the output signal are both less than70ns, and the saturation output power is higher than20W, during the frequency range (f0±1)GHz, the power combining efficiency is calculated to be higher than90%in the whole tested band.