An integrated 60 GHz differential-fed patch array antenna in low-cost QFN package

Abstract

—This paper presents a low-cost and easy-assembly AiP solution for 60 GHz radar sensor applications based on the QFN package. Using traditional PCB process, a 60 GHz differential-fed patch array antenna is proposed. To improve the bandwidth and gain performance, four rectangular parasitic elements are introduced. For miniaturization, a compact differential-fed structure is implemented. To ensure encapsulation and protection, a low-cost plastic package lid is utilized, and its impact on the antenna performance is analyzed theoretically by a transmission-line model. For demonstration, an antenna prototype is designed, fabricated and measured with a balun and probe test structure. With and without the package lid, the 10 dB impedance bandwidth of the proposed antenna is from 55.2 to 66.5 GHz, and from 55.6 to 66.3 GHz, respectively. Moreover, the gain is higher than 7.7 and 7.5dBi, respectively. Measurement results validate negligible impact of proposed package lid on antenna performance, affirming transmission-line model's effectiveness in design methodology.