Study of 140 GHz Waveguide Fed Lenses with Different Dielectric Constant

This paper presents two lens designs working at 140 GHz: an elliptical lens and an extended hemispherical lens. Both dielectric lenses have the same diameter and are fed by a circular waveguide to obtain symmetrical beam patterns. A novel impedance matching method is proposed to minimize the reflection between the feed and lens. Moreover, this impedance matching structure inside the lens is easy to fabricate together with the lens using computer numerical control (CNC) machining or 3D printing. Numerical studies regarding the antenna gain and loss of the material are conducted. The simulated results show that the elliptical lens has more potential due to its higher radiation efficiency and ease of manufacture. The proposed lens antenna is a low-cost candidate and suitable for millimeter-wave radar and wireless communication applications.