Small conformable broadband traveling-wave antennas on platform

Abstract

The invention is a novel solution to circumvent the fundamental gain bandwidth limitations of an antenna of a given size by using a traveling-wave (TW) antenna and strongly coupling it with the mounting platform to enlarge the effective size of the antenna. A preferred form of this invention comprises a conducting ground surface generally curvilinear and conformal to said platform, a broadband TW surface radiator positioned above and spaced apart from said ground surface, an impedance matching structure between the surface radiator and the conducting ground surface, and a reactive impedance matching network positioned on the periphery of said surface radiator.

Description

[0001] Statement Regarding Federally Sponsored Research or Development [0002] The present invention was conceived and created by the inventors without outside financial support. The inventors have elected to assign all rights to Wang Optoelectronics Corporation. Wang Optoelectronics has chosen to license to the U.S. Department of Defense (DoD) a royalty-free license, similar to the terms and conditions of the DoD SBIR (Small Business Innovation Research) program, under a grant sponsored by U.S. Special Operations Command MacDill AFB, FL33621 Contract DoD SBIR No. H92222-07-C-0071 for use of this invention after approval of product development work on this invention. technical field [0003] The present invention relates generally to radio frequency antennas and, in particular, to small conformal broadband antennas on curved platforms. Background technique [0004] Small broadband antennas that can conform to curved platforms have become increasingly important for militar...

AI Technical Summary

Problems solved by technology

Using matching structures in the antenna aperture or using multiple ports will create problems that do not obey the Chu limit

[0011] Third, because Chu's theory is based on an inverse relationship between Q (quality factor) and bandwidth that quickly becomes invalid as Q decreases below about 4, Chu's theory can only be used for high Q narrowband antenna

Therefore, Chu's theory is completely inapplicable for broadband (low-Q) antennas, usually of the non-resonant type

[0012] Fourth, the unrealistic zero-dissipative loss assumption makes Chu's theory unsuitable for those design methods that optimize the gain bandwidth at a small cost of dissipative loss

The actual bandwidth limitation on the upper frequency limit is mainly due to the radiation properties (pattern and polarization) of the antenna; and the actual bandwidth limitation on the lower frequency limit is due to its impedance

[0014] However, these conformal TW antennas beyond the Chu limit are limited to SMM antennas and SW antennas, both of which have conductive ground planes and radiators that are fairly flat and spaced by a constant distance

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