Microwave measurement technology of optical signal based on the helical antenna

In this paper, an optical signal microwave measurement technique based on the resonance performance of a helical antenna is proposed. The helical antenna loaded with a cadmium sulfide (CdS) photoresistor is used as the core detection sensor. When the CdS photoresistor is irradiated, the resistance loaded on the helical antenna changes, which causes the microwave resonance performance to change accordingly. Therefore, according to the measurement of the microwave resonance, the optical signal can be successfully detected. In this experiment, the light source is a power tunable signal source with a working wavelength of 480nm. The minimum detection power is $\mathbf{2.5}\times \mathbf{10}^{-\mathbf{9}}\mathbf{W}$, and the photosensitivity is $\mathbf{R}=\mathbf{0.034dB}/\mathbf{nW}$.