W-band millimeter-wave antenna measurement system using an optical fiber link millimeter-wave generator

We have newly developed a W-band millimeter wave signal generator using an optical second-order harmonic generation technique for a LiNbO3 Mach-Zehnder optical intensity modulator. For generating the millimeter wave from 75 GHz to 110 GHz, our developed signal generation technique uses the signal generator from 18.75 GHz to 27.5 GHz, a microwave amplifier, the LiNbO3 Mach-Zehnder optical intensity modulator, and a photodiode. The system can generate the millimeter wave signal level of more than −30 dBm. We demonstrated antenna radiation pattern measurement for a standard gain horn antenna and an open-ended waveguide probe.

I. Introduction

The W-band (75 GHz to 110 GHz) millimeter wave mostly uses for an automotive collision radar for 77 GHz to 81 GHz, and so on. The millimeter wave band antenna measurement system uses a waveguide and a mixer system that is not easy to handle for antenna measurement. To replace the mixer system, we have already proposed a V-band (50 GHz to 75 GHz) millimeter wave signal generator using a LiNbO₃ Mach–Zehnder intensity modulator (LN modulator) [1] that system can generate the V-band millimeter wave more than −55 dBm [2]. In this paper, we newly developed a W-band millimeter wave generator that consists of a LN modulator and a zero-biased UTC-PD [3]. The system can generate the millimeter-wave more than 75 GHz using an optical second-order harmonic generation technique using input level controlling technique. The system can generate 75 GHz to 110 GHz with more than −35 dBm millimeter wave signal level. Further, we have demonstrated a antenna near field measurement using the proposed system for a W-band standard gain horn antenna and a open ended waveguide probe antenna.