DIRECTIONAL THROUGH GLASS VIA (TGV) ANTENNAS FOR WIRELESS POINT-TO-POINT INTERCONNECTS IN 3D INTEGRATION AND PACKAGING
Seahee Hwangbo, Sheng-Po Fang, Hyowon An, Aric Shorey, Abbas Kazmi and Yong-Kyu Yoon
A directional Through Glass Via (TGV) antenna is designed in a glass interposer layer for W-band (75GHz - 110GHz) wireless point-to-point chip communications with a center frequency of 78 GHz. The TGV is utilized as a main radiator (monopole antenna), which is fed by the coplanar waveguide (CPW) on the top side of the glass substrate, a circular disc is loaded on the tip of the TGV for input impedance matching, and an array of TGV reflectors are placed in proximity along with the perimeter of the circular disc in one side of the monopole antenna, forming a directional radiation pattern in the opposite direction of the reflectors. The directional radiation pattern enables not only to realize point-to-point lateral wireless communications with a distance of up to a few cm in 3D System-in-Packaging (SiP), but also to serve as an electromagnetic shield, preventing the EM signals from being transmitted towards the unwanted directions. With the wireless interconnect approach, enhanced signal integrity over far distance data transmission is expected such as low latency and low cross talk. A test antenna is designed and fabricated on the glass substrate, and a return loss of 21.6 dB at 78 GHz and a 10 dB bandwidth of 16.6 % (70.75 GHz to 83.67 GHz) have been achieved. The measured and simulated radiation frequencies are matched well. The simulated front-to-back ratio and gain of the antenna is 2.3 dBi and 20.3 dB, respectively.
Keywords: Through Glass Via (TGV), millimeter-wave antennas, wireless chip-to-chip communications, wireless interconnects and 3D System-in-Packaing (SiP)