Transmit–receive isolation improvement by a switch sequence adjustment for MMW linear-arrays imaging

Abstract

High transmit-receive isolation between any two adjacent elements in sequentially switched linear arrays guarantees the performance of high-resolution close-range imaging. However, the transmit-receive antenna spacing required in wavelength order makes its isolation deteriorated rapidly in the millimeter wave and higher frequency bands. In this paper, we propose a simple yet effective method to improve transmit-receive isolation by a switch sequence adjustment on the traditional linear arrays. The new switch-mode aims to simply increase the vertical spacing between each transmit-receive pair. To maintain the densely uniform-spatial effective sampling and Fourier transform-based image reconstruction, the principle of equivalent phase center is utilized to analyze the maximum of the possible vertical spacing of each transmit-receive pair is four wavelengths. Experiments verify that the method can efficiently improve transmit-receive isolation by up to 11.5 dB and guarantee the high performance of MMW imaging.

Keywords:

• Millimeter-wave imaging
• synthetic aperture imaging
• transmit–receive isolation
• equivalent phase center error

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work has been supported by the National Natural Science Foundation of Shanghai [21ZR1443600].