Developing an ultra-compact phased-array transceiver for 6G applications

An ultra-compact, low-power 150 GHz radio module enabling high data rates in mobile devices has been developed by researchers from Japan. Targeting 6G user equipment, the proposed design integrates a phased-array transceiver with several key innovations to overcome the main challenges of operating at frequencies in the 150 GHz band. This work could thus pave the way to unprecedented connectivity in terminal devices, way surpassing existing 5G technology.

The sixth-generation (6G) mobile communication technology aims to revolutionize wireless connectivity by achieving data rates exceeding 100 Gbps, far surpassing the current capabilities of 4G and 5G. To reach such an ambitious target, scientists and engineers are turning to the sub-terahertz D-band (110–170 GHz), which offers the wider bandwidth necessary for ultra-high-speed, high-capacity communications.

However, harnessing these frequencies presents unprecedented technical challenges, such as significant propagation losses in free space and difficulties in implementing essential circuit components like amplifiers and switches. Because of this, existing D-band transceivers have been designed mostly for 6G base stations or backhaul applications, requiring large chip sizes and bulky antenna modules. This hinders their integration into user equipment such as smartphones and Internet of Things devices, which could truly capitalize on 6G’s transformative potential.

To overcome these barriers, a research team led by Professor Kenichi Okada from Department of Electrical and Electronic Engineering, School of Engineering, Institute of Science Tokyo (Science Tokyo), Japan, in collaboration with the National Institute of Information and Communications Technology (NICT) and others, has developed an innovative, ultra-compact, low-power antenna-in-package radio module for 150 GHz operation. Their groundbreaking work will be presented at the prestigious international conference: the 2025 Symposium on VLSI Technology and Circuits in Kyoto starting June 8, 2025.

The breakthrough lies in the team’s innovative circuit design approaches that address the fundamental limitations of existing phased-array systems. At the heart of their solution is an injection-locked tripling phase shifter, which eliminates the need for local oscillator buffers that typically consume significant power and chip area. By directly connecting to the mixer, this design maximizes voltage amplitude while maintaining precise frequency control.

Another key innovation is in the mixer itself, namely a bi-active sub-harmonic mixer. It operates at half the local oscillator frequency and effectively cancels problematic oscillator leakage. Moreover, its dual functionality enables both transmission and reception modes while maintaining high performance in an extremely compact footprint.

The researchers also integrated an antenna switch directly into the amplifier matching networks, skillfully eliminating parasitic capacitance issues that plague conventional designs. This integrated approach minimizes signal losses and enables sharing of power amplifier components between transmission and reception modes, making the design even more area efficient.

“While conventional modules using millimeter-wave bands have had maximum data rates of a few Gbps, this new wideband 150 GHz module enables high-capacity wireless communication at several tens of Gbps in mobile devices,” remarks Okada, “This advancement paves the way for novel application markets, such as highly realistic mobile VR and XR usage in medical operating rooms, offering experiences with unprecedented realism.”

Surprisingly, the completed eight-element module measures just 8.4 mm by 20 mm, which is remarkably compact for such high-frequency operation. Experimental tests revealed impressive performance metrics for its size: 56 Gbps maximum data rates, a record-setting 25.7 dBm effective radiated power, and exceptional power efficiency, with just 150 mW consumption per element in transmission mode. “Compared to conventional phased-array radios designed for 6G, this module achieves very high-power-density, making it suitable not only for base stations but also for compact, low-power terminal applications,” notes Okada.

The design considerations adopted in this work will accelerate the development of next-generation wireless applications, spanning immersive entertainment, precision medical procedures, and advanced industrial automation. Overall, this achievement represents a crucial step toward realizing 6G’s full potential in everyday mobile devices and sophisticated industrial equipment alike.

This work is partially supported by the Ministry of Internal Affairs and Communications in Japan (JPJ000254).

Authors:

Yudai Yamazaki¹, Sunghwan Park¹, Takaya Uchino¹, Chenxin Liu¹, Jun Sakamaki¹, Yohei Morishita², Akihiro Egami², Ryosuke Hasaba², Ken Takahashi³, Tomoki Abe², Tomohiro Murata², Yoichi Nakagawa², Takashi Tomura¹, Hiroshi Taneda⁴, Kei Murayama⁴, Makoto Tsukahara⁴, Hiroko Ota⁴, Yoko Nakabayashi⁴, Chun Wang¹, Hans Herdian¹, Yi Zhang¹, Zheng Li¹, Wenqian Wang¹, Hongye Huang¹, Dingxin Xu¹, Sena Kato¹, Michihiro Ide¹, Yuncheng Zhang¹, Hiroyuki Sakai¹, Kazuaki Kunihiro¹, Atsushi Shirane¹, Koji Takinami², Kenichi Okada^1*
*Corresponding author

Title:

A 150 GHz High-Power-Density Phased-Array Transceiver in 65nm CMOS for 6G UE Module

Journal:

Technical Digest of the 2025 Symposium on VLSI Technology and Circuits

Affiliations:

¹Institute of Science Tokyo, Tokyo, Japan
²Panasonic Industry Co., Ltd., Japan
³Panasonic System Network R&D Lab., Japan
⁴Shinko Electric Industries Co. Ltd., Japan

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