Tri-axis Polarized Loop Antenna for mmWave Wireless Inter/intra Chip Communications

We present a tri-axis polarized dual loop antenna for inter/intra chip/board wireless communications in a 3D system-in-package (SiP). The advantages of the presented antenna are as follows: 1) the loop antenna enables inter/intra chip/board communications in all three directions along x, y, and z-axis at 77 GHz; 2) also, the two loops can be designed to produce rather arbitrary main radiation robes without being orthogonal each other, which facilitates improved antenna efficiency in desirable communication directions; 3) since two vertical via holes are the part of the design, this loop antenna can be easily integrated with any through-substrate via structures in a compact footprint of 1.1 mm2. Analytical study for the radiation patterns is carried out and the resultant radiation patterns are compared to simulated ones with High Frequency Structure Simulator (HFSS, ANSYS Inc.). The simulated efficiency and antenna peak gain are 94 % and 3.14 dBi, respectively. A prototype is fabricated on a 254 μm thick RT duroid 5880 substrate using microfabrication and milling machines. Antenna performance is characterized using vector network analyzer with scattering parameters.