THz Chip Detect Objects In Three Dimensions
Researchers from Princeton University have developed a way to accurately detect objects in three dimensional space using on-chip THz antennas. The developed concept exploits frequency-dispersive leaky-wave antennas – end-fed strips, 1.7mm long, with transverse slots spaced at 43μm intervals.
The frequency between 360 and 400GHz has to be injected into one end resulting in a fan of energy leaving the antenna at right angles to its long axis. According to the research data, the higher the frequency, the further tilted away from the feed end is the fan: 360GHz leaves at right angles and 400GHz tilts the fan at 40° to the normal, so scanning from 360 to 400GHz sweeps the fan from 0° (normal) to +40°.
Isolation for end-to-end in an antenna is 20dB, which allows receivers to be connected to the far end of each of the antennas, giving them similar frequency-dependent fan-like sensitivity and directivity.
On the transmitter side chip, energy is delivered at 60-66GHz, amplified, then frequency is doubled and tripled to drive the antenna. In the receiver, there is a mixer and 0 – 15GHz IF (Intermediate Frequency) amplifier at the antenna feeding off-chip signal processing. An off-chip local oscillator feeds 60-67GHz to on-chip doubler and tripler for the mixer.
The research was presented at the ISSCC 2021.