Balanced Intermodulation Reference With Flat Frequency Response Using Nonlinearity Equalization

This letter proposes a balanced intermodulation (IM) reference source with constant IM magnitude-frequency response using the nonlinearity equalization method. In the design, the diode is working as the nonlinear source, while the excitation carriers are equalized versus frequency to stimulate diode; thus, a flat IM3 magnitude-frequency response can be obtained accordingly. The experiment demonstrates this designed IM source can provide flat IM3 magnitude-frequency response at 700 MHz, 1800 MHz, and 2600 MHz IM3 test bands with a fluctuation error less than 1.5 dB, while three typical reference magnitudes ranges from −80 dBm, −90 dBm to −100 dBm at 2 × 43 dBm are demonstrated also.