Wideband Multimode Leaky-Wave Feed for Scanning Lens-Phased Array at Submillimeter Wavelengths

Abstract

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 fieldof-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.

A Dual-Polarized 27 dBi Scanning Lens Phased Array Antenna for 5G Point-to-Point Communications

“…The main driver for the optimization of the lens shape is the maximization of its aperture efficiency, since it directly impacts the level of grating lobes [12]. Therefore, we used elliptical lenses [17], [26] with eccentricity e = 1/ √ ε r ( ε r = 2.34), truncation angle θ 0 seen from the lower focus of the lens (see Fig.…”

“…To achieve a wider BW, larger gain, and larger steering angles, we propose to use a scanning lens phased array architecture combined with leaky-wave antenna (LWA) feeds, which was introduced in the framework of the ERC grant LAA-THz-CC [11], and more recently in [12]. Small lenses phased arrays with limited steering ranges have been developed in millimeter waves [13], as well as combining with focal plane arrays in one dimension to enlarge the steering range [14].…”

“…Both arrays are arranged in a hexagonal grid with 2λ 0 spacing at 28 GHz. The movable dielectric lens array, used as the add-on layer, ensures low grating lobe level (GLL) thanks to a highly directive and steerable array element pattern [12].…”

“…As a result, the array pattern, obtained as the product between the array element pattern and the array factor, shows a low GLL (blue line). To achieve such a low GLL over wide steering angles, array elements of high aperture efficiency are needed over the required frequency band and steering ranges [12].…”

“…1(b) can be used for transmitting two independent signals. In [12], the proposed array, operating at submillimeter wavelengths, is based on silicon lenses excited by leaky-wave waveguide feeds. In this work, the lens array concept is adapted to the technology requirements for 5G communications.…”