Design of Active Frequency Multiplier for X-Band Radar Application

A non-linear hetero-junction bipolar transistor (HBT) is used for designing an active frequency doubler for a wide band radar application. Using the harmonics of the transistor, band pass filters, and driver amplifier for the signal amplification we can design a frequency multipliers and harmonic generators that produce various frequency multiples of an input fundamental frequency. The output power is also three dB higher and offers an excellent multiplier conversion efficiency compared to a single HBT frequency doubler. According to the simulation outcomes, when the fundamental input power is 0 dBm, the second harmonic output power is -8.33 dBm, and when additional harmonics are filtered out and the signal is amplified, the fundamental frequency rejection is greater than 80 dBc and the third harmonic rejection is greater compared to first harmonic frequency.