Beam Scanning of Silicon Lens Antennas Using Integrated Piezomotors at Submillimeter Wavelengths

Abstract

This paper presents a lens antenna that scans the beam using an integrated piezo-motor at submillimeter wave frequencies. The lens antenna is based on the concept presented in [1], a leaky wave waveguide feed in order to achieve wide angle scanning and seamless integration with the receiver. The lens is translated from the origin of the waveguide producing the scanning of the beam over a 50 deg Field of View (FoV) (or about 6.25 beamwidths) with a maximum scanning loss of 1 dB. The lens movement is achieved with a piezoelectric motor that is integrated within the antenna and receiver block. A prototype was built and measured at 550 GHz achieving scanning beam angles close to 20 degrees with only 0.6 dB of loss. The scanning of the 50 deg FoV, which corresponds to a lens displacement of approximately 2 mm, takes about 0.9 s achieving a scanning rate of 0.75 Hz of the FoV. The accuracy in continuous mode of the piezo actuator has been measured to be less than 28µm in the worse of cases for displacements of 2 mm, which corresponds to a beam steering of 0.76 deg, much smaller than the antenna half power beamdwith of 8 deg.

Terahertz Beam Steering Technologies: From Phased Arrays to Field‐Programmable Metasurfaces

“…Refraction is a classical way to change direction of the EM beams and the mechanical scanning method based on lens antennas is commonly used to realize the continuously changeable refraction angles. Alonso‐delPino et al found a way to steer a beam by changing the position of the feed . Figure a shows the schematic of a 550 GHz silicon lens antenna integrated with a leaky‐wave waveguide feed and a piezoelectric motor.…”

“…b) Measured (solid line) and simulated (dashed line) far‐field radiation patterns with different scanned positions for the incident wave frequency of 550 GHz. Reproduced with permission . Copyright 2019, IEEE.…”

“…Some other approaches that have been well examined at microwave frequencies are still potentially useful in the terahertz frequency region. These approaches included mechanical scanning lens antennas, frequency‐scanning antennas, pattern reconfigurable antennas, and multibeam switching technology …”

A Low-Profile and High-Gain Frequency Beam Steering Subterahertz Antenna Enabled by Silicon Micromachining

“…The silicon lens was micromachined and required a total amount of 13 wafers for the lower gain version (32 dBi). The same authors recently demonstrated beam steering capabilities with a similar design at 550 GHz [12], however, the presented solution requires movement of the lens by external mechanics, which increases the overall complexity, cost, and volume of the system. Frequency scanned antennas have been shown as a good alternative to mechanically scanned systems due to their lower cost, size, and complexity.…”

“…Silicon micromachining has been an enabling technology for low-loss waveguide components at sub-THz frequencies [1], [12], [21]- [23]. Some of the advantages of silicon micromachining are the ability to fabricate features down to the micron scale, batch production, better tolerances, and better batch-to-batch uniformity.…”