This article presents the development of a focal plane array (FPA) for terahertz imaging applications with a near diffraction-limited resolution achieved through a very tight sampling of the focal plane. The antenna array is integrated with direct detectors in a 22-nm CMOS technology and operates from 200 to 600 GHz. The tight sampling of the focal plane is realized by using a combination of leaky-wave radiation and a dual-polarized connected array configuration that closely resembles a chessboard. By utilizing both the polarizations in the chessboard design, the number of array elements per unit area is effectively doubled. The geometry of the chessboard array was co-optimized together with that of a silicon elliptical lens to achieve both high aperture efficiency and beam overlap. Measurements in the WR2.2 band of a fabricated demonstrator showed that an aperture efficiency of −4.1 dB was realized at 400 GHz. The average gain roll-off between two diagonally adjacent array elements was measured to be −1.5 dB at 400 GHz. Compared to the reference configuration of an idealized, equivalently sampled hexagonal FPA, the improvement in gain at the edge of coverage yields 1.2 dB, which includes 1.9 dB of ohmic losses in the chessboard array. The agreement between measurements and simulations proved to be within 1 dB from 325 to 475 GHz.

In this paper, we present a quasi-optical power distribution architecture based on the use of an integrated lens antenna that generates a uniform aperture field distribution. By using such distribution in combination with an integrated lens array, an efficient and scalable quasi-optical power distribution can be achieved at THz frequencies. The proposed architecture is based on a leaky-wave waveguide feed that illuminates an elliptical lens with a top-hat distribution. This method can distribute the power from one antenna to a 7-pixel lens array in a hexagonal configuration with a power coupling efficiency of nearly 60%. This scheme could be potentially used for the local oscillator power distribution in heterodyne THz arrays. A prototype at 450-615GHz has been developed and characterized, achieving an aperture efficiency higher than 80%.

We present the design, fabrication and characterization of a broadband lossless matching layer for silicon lens arrays. The proposed matching layer is based on silicon frusta (truncated pyramids) on top of the lens array fabricated by means of laser ablation. This matching layer is advantageous over quarter-wavelength dielectric matching layers since it covers more than an octave of bandwidth. We compare the performance of this matching layer with the commonly-used parylene-C matching layer at the center of the targetted band (500 GHz) in a lens-antenna integrated system. We measure a 1.6 dB higher transmission of the proposed silicon frusta matching compared to the parylene-C matching layer.

In this article, we propose a hybrid electromechanical scanning lens antenna array architecture suitable for the steering of highly directive beams at submillimeter wavelengths with field-of-views (FoV) of ±25°. The concept relies on combining electronic phase shifting of a sparse array with a mechanical translation of a lens array. The use of a sparse-phased array significantly simplifies the RF front-end (number of active components, routing, thermal problems), while the translation of a lens array steers the element patterns to angles off-broadside, reducing the impact of grating lobes over a wide FoV. The mechanical translation required for the lens array is also significantly reduced compared to a single large lens, leading to faster and low-power mechanical implementation. In order to achieve wide bandwidth and large steering angles, a novel leaky wave lens feed concept is also implemented. A 550-GHz prototype was fabricated and measured demonstrating the scanning capabilities of the embedded element pattern and the radiation performance of the leaky wave fed antenna.

It is difficult to package and interconnect components and devices at millimeter-waves (mm-waves) due to excessive losses experiences at these frequencies using traditional techniques. The problem is multiplied manifold at terahertz (THz) frequencies. In this article, we review the current state of THz packaging and describe several novel techniques. As we will show, micromachined packaging is emerging as one of the best choices for developing advanced THz systems.