On-Chip Antenna Design for Terahertz Communications

On-chip antennas for terahertz (THz) communications represent a convergence of microwave engineering, advanced materials and integrated-circuit fabrication, aiming to deliver compact radiating elements directly on semiconductor substrates. The THz band, spanning roughly 0.1–10 THz, offers vast unexploited bandwidth for ultra-high-speed wireless links, imaging and sensing. However, on-chip integration at these frequencies is hindered by high substrate losses, surface-wave propagation and severe impedance-matching challenges. Recent advances have harnessed substrate-integrated waveguide (SIW) cavities, metamaterial-inspired and metasurface layers to suppress spurious modes and channel electromagnetic energy efficiently to radiating patches. By stacking metal and dielectric layers—often using gallium arsenide, silicon or polymer substrates—researchers have engineered leaky-wave structures and capacitive-inductive networks that extend effective aperture without compromising footprint. Such designs have achieved gigahertz-scale bandwidths, multi-dBi gains and efficiencies exceeding 70 per cent, paving the way for THz front-end modules, on-chip wireless interconnects and short-range high-capacity links.

Research from Nature Portfolio

Recent studies have demonstrated a high-performance antenna-on-chip fabricated on gallium arsenide, combining SIW cavities with a metasurface layer of sub-wavelength slots. This five-layer stack confines the feedline within an SIW cavity to mitigate surface-wave losses and couples energy through etched slots to dual wrench-shaped radiators. Operation over 0.445–0.470 THz yields a 25 GHz bandwidth, average return-loss of –27 dB, a 4.6 dBi gain and 74 per cent radiation efficiency, highlighting viability for THz system-on-chip integration. A foundational work explored a polyimide-based on-chip antenna incorporating a composite right/left-handed transmission line metasurface. Concentric metal and dielectric rings behave as series capacitances and shunt inductances, extending the effective aperture while suppressing surface waves. Covering 0.350–0.385 THz, the structure achieves an 8.15 dBi gain and 65.7 per cent efficiency in a 6 × 6 × 1 mm3 footprint, illustrating how engineered unit-cells can reconcile compactness with high performance.

On-Chip Antenna Design for Terahertz Communications publication trend

The graph below shows the total number of articles in on-chip antenna design for terahertz communications across all publications each year (not limited to Nature Index journals).

Technical terms

On-chip antenna: A miniature radiating element fabricated directly on a semiconductor or dielectric substrate for wireless signal coupling in integrated circuits.

Substrate Integrated Waveguide (SIW): A planar waveguide formed by metal vias or walls within a dielectric substrate to confine and guide electromagnetic energy with reduced losses.

Metasurface: A two-dimensional array of engineered scatterers or slots that imparts tailored phase, amplitude or polarisation control to incident waves at sub-wavelength scales.

Metamaterial: An artificial medium structured on a scale smaller than the wavelength, exhibiting unconventional effective permittivity and permeability to enhance antenna performance.

Composite Right/Left-Handed Transmission Line (CRLH-TL): A transmission-line model combining series capacitances and shunt inductances to achieve both right-handed (conventional) and left-handed (backward-wave) propagation characteristics.

Surface waves: Unwanted guided modes that propagate along the substrate layer, leading to power loss and pattern distortion in on-chip antennas.

Radiation efficiency: The ratio of power radiated by the antenna to the total input power, accounting for dielectric and conductor losses.

References

1. High performance antenna-on-chip inspired by SIW and metasurface technologies for THz band operation. Scientific Reports (2023).
2. High-Gain Metasurface in Polyimide On-Chip Antenna Based on CRLH-TL for Sub-Terahertz Integrated Circuits. Scientific Reports (2020).
3. A Comprehensive Survey on Antennas On-Chip Based on Metamaterial, Metasurface, and Substrate Integrated Waveguide Principles for Millimeter-Waves and Terahertz Integrated Circuits and Systems. IEEE Access (2022).
4. Compact and Low-Profile On-Chip Antenna Using Underside Electromagnetic Coupling Mechanism for Terahertz Front-End Transceivers. Electronics (2021).