A method includes pointing a receive beam of a retro-directive antenna array attracted to a jammer circuit instead of a remote transmitter away from the jammer circuit toward the remote transmitter by a first angle based on coarse manual means therefor implemented in electronic circuitry associated with the retro-directive antenna array. The electronic circuitry includes a number of mixers, each of which is configured to mix a Local Oscillator (LO) signal generated from a Voltage Controlled Oscillator (VCO) with a signal received at an antenna element of the retro-directive antenna array. The method also includes automatically fine pointing the receive beam toward the remote transmitter by a second angle following the coarse pointing thereof by the first angle such that the receive beam exactly points to, and tracks, the remote transmitter. The automatic fine pointing is effected through a secondary automatic servo loop implemented in the electronic circuitry.

The disclosure relates to suppressing surface waves in a communication device for a wireless communication system. The communication device includes a dielectric layer extending along a plane between a chassis and a glass layer, an antenna element configured to emit a radio wave, and a retroreflective structure extending inside the dielectric layer and being located adjacent to the antenna element, and where the retroreflective structure is configured to reflect the radio wave in an angle non-parallel to the plane. The retroreflective structure hence prevents parasitic channeling of the antenna energy into surface waves in and behind the glass layer and directs the radiation into the desired direction.

One or more input signals are used to generate a Pseudo noise generator and re-inject the signal to obtain a more efficient method of control of a receiver using adaptive antenna array technology. The antenna array automatically adjusts its direction to the optimum using information obtained from the input signal by the receiving antenna elements. The input signals may be stored in memory for retrieval, comparison and then used to optimize reception. The difference between the outputs of the memorized signals and the reference signal is used as an error signal. One or multiple Modal antennas, where the Modal antenna is capable of generating several unique radiation patterns, can implement this optimization technique in a MIMO configuration.

A method of operating a frequency modulated continuous-wave radar can include transmitting CHIRP signals from a plurality of antennas of the frequency modulated continuous-wave radar, receiving, via the plurality of antennas, signals including asynchronously modulated retro-directive signals from at least one remote radio frequency tag generated responsive to the CHIRP signals, generating difference Intermediate Frequency signals from the CHIRP signals transmitted and the signals received, and performing a first transform operation on the difference Intermediate Frequency signals to detect occurrence of the asynchronously modulated retro-directive signals in the difference Intermediate Frequency signals.

Various antennas elements including antennas arrays can support various communication technologies and can be integrated into different components or subcomponents of a vehicle, including various vehicle light assemblies. The vehicular antennas elements include low profile and/or concealed antenna elements that are inconspicuous aesthetically and do not affect or substantially affect vehicle aerodynamics.

A retroreflective antenna according to one embodiment includes: an antenna main body for retroreflecting incoming radio waves; and a passive notch filter, in which the antenna main body includes a plurality of pairs of antenna elements, and a plurality of transmission lines provided corresponding to the plurality of pairs of antenna elements, each pair of antenna elements in the plurality of pairs of antenna elements is disposed point-symmetrically with respect to a reference point in the antenna main body, each of the plurality of transmission lines connects corresponding pair of antenna elements among the plurality of pairs of antenna elements, electrical lengths of the plurality of transmission lines are the same, and the passive notch filter is provided in at least one transmission line among the plurality of transmission lines.