Abstract:For the situation that the current commercial impedance analyzer is expensive,this paper designed a simple impedance meter with a dual directional coupler and an amplitude and phase detection chip AD8302. Dual directional coupler is mainly used to constitute reflectometer circuit, separating the input signal and the reflected signal; AD8302 is mainly used to measure these two signals' amplitude gain and phase difference. After combining the two parts,to get load impedance by measuring the reflection coefficient. By measuring the chip resistor during the frequency of 75~85 MHz and receiving that its maximum relative error of real part is 3.8%,imaginary part presents a smaller reactance. The results show that the simple impedance meter can achieve impedance measurement preliminary.