A THz Imaging System Using Linear Sparse Periodic Array

THz sparse periodic array imaging system using compressed sensing

“…This properly configured SPA consists of Nt Tx elements with a dt spacing and Nr Rx elements with a dr = 0.5 ⋅ Nt ⋅ dt spacing. Thus, it can work comparably to a longer effective array that consists of Nt ⋅ Nr elements with a uniform element spacing of dt [18], maintaining high image quality with fewer array elements [10,18,19]. However, the traditional SPA is designed with Tx and Rx elements lined up so that the spacing between Tx and Rx elements may be too small to place two elements or channels, therefore we have studied a more practical scheme that Tx and Rx elements are separated by a distance S TR as shown in Fig.…”

“…However, the traditional SPA is designed with Tx and Rx elements lined up so that the spacing between Tx and Rx elements may be too small to place two elements or channels, therefore we have studied a more practical scheme that Tx and Rx elements are separated by a distance S TR as shown in Fig. 2 [10]. The design guideline and performance of this kind of THz SPA imaging system have been fully investigated in [10].…”

“…2 [10]. The design guideline and performance of this kind of THz SPA imaging system have been fully investigated in [10]. Besides, we have demonstrated that the effect of the separating distance S TR is not significant, but it would be preferred to keep the separating distance as close as possible for the best image performance [10].…”

“…Therefore, the achieved width of field of view (FOV) on a flat target by using this SPA is 0.5•Nt•Nr•dt and the height of FOV is the mechanical scanning length [10]. The theoretical cross-range resolution can be derived by…”

“…This scheme has been demonstrated working well at a low frequency up to 75-90 GHz band with a small sampling interval of the order of λ for the short-range distance imaging [9], but it fails to clearly identify the target at THz band of 340 GHz due to its narrow aperture of the effective array and optical scanning scheme [1]. Thus, we have investigated an SPA imaging system working at 220 GHz with the larger element spacing in both simulation and experiment, based on the traditional generalised synthetic aperture focusing technique (GSAFT) [10].…”