High-power photonic antenna arrays
Date
2017
Authors
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Journal ISSN
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Publisher
University of Delaware
Abstract
As RF phased array antennas continue to evolve to meet the demands of modern wireless applications, several pressing challenges are making it difficult for electronic-based systems to adapt. New systems are desired that exhibit ultra-wideband (UWB) performance, improved size, weight, and power (SWaP) characteristics, and provide functionality extending into the mmW regime. However, inherent to the current phased array paradigm is the inclusion of bulky and interferent electronic feed circuitry which has proven prohibitive in bringing these goals to fruition. ☐ In this work, a photonic solution is proposed to enable progress in these areas. An all-dielectric, fiber optic phased array feed is presented, which demonstrates inherent electromagnetic field immunity, small size and weight, and wide operational bandwidth. These feed properties enable the preservation of the theoretical UWB response and low-profile of a variety of high-performance antennas. To provide sufficient RF output power, high-power charge-compensated modified uni-traveling carrier (CC-MUTC) photodiodes are directly integrated into the feed points of these antennas. By properly designing the “photonic antennas” to compensate for the capacitive reactance and heat dissipation of the photodiodes, they are shown to demonstrate effective isotropic radiated power (EIRP) exceeding 1 W, and RF power conversion efficiency (PCE) approaching 50% close to mmW. ☐ A number of increasingly complex, high-power photonic phased array systems are studied for modern RF applications. Aperture coupled patch antennas (ACPAs) are designed for 22 and 28 GHz operation, which demonstrate near ideal performance metrics. A 28 GHz photonic ACPA array is also fabricated for narrowband 5G applications. Later, photonic connected array antennas are investigated, which realize efficient 5-20 GHz response, while retaining the excellent SWaP qualities of elementary dipole elements. The fiber optic feed is shown to mitigate common problems that inhibit the UWB operation of traditional electronic phased array antennas, such as scan blindness and unbalanced feeding. And lastly, a photonic tightly coupled array is fabricated, which improves antenna output power and beam steering through addition of a ground plane. Simulations indicate that large-scale photonic TCAs can have similar bandwidth performance to that of their electronic counterparts, while being more flexible in their potential physical deployment scenarios and operating bands of interest.
Description
Keywords
Applied sciences, High-power photodiodes, Phased array antennas, RF photonics