150 GHz-band Coreless High Multilayer Antenna-in-Package for 6G

In recent years, data have been exchanged by communication terminals everywhere in our daily lives, and the development of low-latency communication technologies for use in medical devices, factory automation, and autonomous driving has been gaining momentum. In order to meet the increasing demand for communications in the future, MIMO (Multiple Input Multiple Output) using the sub-THz band, which has a wider bandwidth available, is expected to realize even higher speed and capacity communications. At frequencies of 151.5 to 164 GHz, the wavelength is approximately 1.9 mm, so a multi-element compact antenna module with antennas of 1 mm or less in line can be realized. Challenges to the widespread use of MIMO antenna modules for high-frequency applications are transmission loss due to the increased number of wiring paths associated with the increased number of antenna elements, and miniaturization for installation in edge devices. In this development, we attempted to solve the problem of transmission loss by selecting low dielectric constant and low dielectric loss tangent materials and using the latest printed circuit board technology to create an antenna with a waveguide that is easy to mass-produce. We also Developed a coreless substrate process to produce small AiP (Antenna-In-Package) substrates that can be miniaturized and reduction in height. Environmental load tests (-55 ⇔ 125 deg.C) were conducted on the prototype AiP substrate, and the 7 stacked via passed 1000 cycles, confirming its practical reliability. The substrate size of this AiP is 8mm x 20mm x <1mmt, which is small enough to be mounted on wearable devices with narrow mounting areas, and it is expected to be widely used in society.