Summary：Exciting mmWave Chip Advance Unlocks Faster 5G with hBN Switches **Introduction** Researchers have

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Exciting mmWave Chip Advance Unlocks Faster 5G with hBN Switches

**Introduction**
Researchers have demonstrated a new way to push millimetre‑wave (mmWave) performance beyond today’s limits by embedding two‑dimensional hexagonal boron nitride (hBN) radio‑frequency switches directly onto gallium nitride (GaN) microchips. The hybrid approach creates programmable monolithic microwave integrated circuits (MMICs) that can steer and shape signals at frequencies above 30 GHz with far lower loss than conventional silicon‑based designs. The breakthrough, reported in a joint paper from a university‑industry consortium, could accelerate the rollout of ultra‑reliable 5G‑Advanced networks and lay groundwork for future 6G systems.

**Key Developments**
The core innovation lies in the co‑integration of atomically thin hBN layers with GaN high‑electron‑mobility transistors (HEMTs). By transferring a few‑layer hBN film onto the GaN surface and patterning it into nanoscale RF switches, the team achieved insertion losses below 0.2 dB at 28 GHz and isolation exceeding 30 dB—figures that rival the best MEMS switches while retaining the robustness of solid‑state devices. Because hBN is chemically inert and thermally stable, the switches survive the high‑temperature processes required for GaN fabrication, eliminating the need for separate packaging steps. Programmability comes from electrostatic actuation: applying a few volts across the hBN layer changes