Range limited antenna includes at least two sets of antenna elements and an RF signal processing network connected to each set of antenna elements. The network has a function, F(.XI.,x)=.PHI..sub.A(x)-.PHI..sub.B(x)+.PHI..sub.C(x)-.PHI..sub.D(x) . . . +.PHI..sub.N-1(x)-.PHI..sub.N(x), where x is a signal, .PHI..sub.A(x) is the phase angle of signal x at the first element set, .PHI..sub.B(x) is the phase angle of signal x at the second element set, .PHI..sub.N(x) is the phase angle of signal x at the set N, and .XI. contains all additional parameters which bear on the system. The network is configured to pass a signal for which F(.XI.,x)>.epsilon., where .epsilon. is a threshold amount, such that the antenna has gain to signals within a radius and has attenuation outside the radius.Range limited antenna764298605/01/201019/09/20072010839Althouse; Mark L. G.US Patent and Trademark OfficeGoogle Patent Searchpatentimages.storage.googleapis.com/US7642986B1/US07642986-20100105-D00000.pngUniquephisignalphase anglelimited antennaantenna elementssecond element setfirst element setsignal processing networksetradius