Ultra-compact radio module enables 6G applications

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

6G mobile communication technology aims to revolutionise 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 ultrahigh-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 capitalise on 6G’s transformative potential.

To overcome these barriers, a research team led by Professor Kenichi Okada from the Institute of Science Tokyo, in collaboration with Japan’s National Institute of Information and Communications Technology (NICT) and others, developed an ultra-compact, low-power, antenna-in-package radio module for 150 GHz operation. Their work was presented at the 2025 Symposium on VLSI Technology and Circuits, held in Kyoto in June.

The team’s breakthrough lies in their 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 maximises voltage amplitude while maintaining precise frequency control.

Another innovation is the mixer itself, which is 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, thus eliminating parasitic capacitance issues that plague conventional designs. This integrated approach minimises 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 millimetre-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,” Okada said. “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.”

The completed eight-element module measures just 8.4 x 20 mm, which is considered remarkably compact for such high-frequency operation. Experimental tests also revealed impressive performance metrics for its size: 56 Gbps maximum data rates, 25.7 dBm effective radiated power (said to be a new record), and just 150 mW of power 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,” Okada said.

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

Image highlights a compact 20 x 8.4 mm transceiver module operating in the 142–164 GHz band. Featuring integrated ICs and antennas, the 8-element array is designed for scalable, low-cost 6G communication systems.