Radar Cross Section of Air- and Space-Borne Antennas as Functions of Their Load Impedance

摘要

The probability of detecting an airborne target by radar depends on its radar cross section (RCS). It is well known that in the very high frequency, ultra high frequency, microwave, and millimeter wave bands, airborne antennas are strong contributors to the RCS. Experience has shown that the RCS of an antenna may vary by 20 to 30 dB or even more, depending on the load impedance of the electronic circuitry that is connected with the antenna. Whereas the mechanical part of an airborne antenna is usually slow-moving or rigid, the electronic circuitry connected with the structure can be built to be variable and flexible, so as to respond speedily and accurately to inputs of a complex nature. For special cases discussed in the report, the conditions under which the RCS can be minimized or reduced to zero are investigated. The method can be used in combination with, or to replace, other schemes of RCS reduction. Also, the basic idea behind the method can be applied to a much more general class of sophisticated weapon systems. Finally, it should be noted that the same basic method can be used to enhance the RCS.