A technique is described where the switch and/or tunable control circuit for use with an active multi-mode antenna is positioned remote from the antenna structure itself for integration into host communication systems. Electrical delay and impedance characteristics are compensated for in the design and configuration of transmission lines or parasitic elements as the active multi-mode antenna structure is positioned in optimal locations such that significant electrical delay is introduced between the RF front-end circuit and multi-mode antenna. This technique can be implemented in designs where it is convenient to locate switches in a front-end module (FEM) and the FEM is located in vicinity to the transceiver.

Aspects of the disclosed technology relate to an active array system that can form and steer a directed beam across its aperture. The disclosed array system utilizes a novel configuration that significantly reduces a number of transmit and receive elements. In some aspects, the disclosed array system can be configured with a modular design, for example, to permit the extension of the transmit/receive array, e.g., to increase/decrease aperture size. In other aspects, the disclosed array system may be configured to dispose the elements of either the first or second group of radiators in a modular fashion.

A roadside apparatus according to the first aspect includes: a housing including an antenna mounting surface; an antenna connection terminal being provided on the antenna mounting surface, and supporting both a rod antenna and a planar antenna; and a circuit being housed in the housing, and being configured to perform road-to-vehicle communication via a connection antenna connected to the antenna connection terminal. An area of the antenna mounting surface is equal to or larger than an area of the planar antenna. An antenna selected out of the planar antenna and the rod antenna is connected as the connection antenna to the antenna connection terminal.

An isolated magnetic dipole (IMD) antenna system can include an isolated magnetic dipole antenna radiating element including a body portion defining a body plane, the body portion comprising an isolated magnetic dipole element, and one or more angled edge portions disposed along at least one edge of the body portion, the one or more angled edge portions angularly offset with respect to the body plane.

A main antenna arrangement is configured to receive with a pre-configured first directional radiation pattern having a first beam with a first beamwidth and to provide first received signals at a first output, and at least one auxiliary antenna is configured to receive with a pre-configured respective second directional radiation pattern having a second beam with a second beamwidth, different from the first beamwidth and to provide second received signals at a second output. Interference cancelling circuitry is configured to control the amplitude and phase of the second received signals received from the at least one auxiliary antenna to produce weighted second received signals and combine the weighted second received signals with the first signals received from the main antenna arrangement to reduce a level of interference signals received by the main antenna arrangement in relation to a level of wanted signals received in the main antenna arrangement.

A communication system utilizing reconfigurable antenna systems is described where beam steering and null forming techniques are incorporated to limit the region or volume available for communication with client devices. The communication system described restricts communication to defined or desired area and degrades signal strength coverage outside of a prescribed region. An algorithm is used to control the antenna system to monitor and control antenna system performance across the service area. This antenna system technique is applicable for use in communication systems such as a Local Area Network (LAN), cellular communication network, and Machine to Machine (M2M).

An adaptive array antenna system receives a desired wave arriving through K time slots each allocated to one of K transmitting stations. In the adaptive array antenna system, an adaptive control device includes a correlation matrix calculating unit, a correlation matrix storing unit, an inverse matrix calculating unit, and a weighting factor calculating unit. The inverse matrix calculating unit acquires a correlation matrix having been calculated at previous time for another time slot other than the current time slot from the correlation matrix storing unit, regards the acquired correlation matrix as an interference noise correlation matrix, and calculates an inverse matrix of the interference noise correlation matrix. The weighting factor calculating unit calculates values of a plurality of weighting factors used by a beamforming unit using the inverse matrix.

A system may include an optical phased array, a photodiode array, and a radiofrequency (RF) antenna element array. The optical phased array may be configured to: receive a laser signal from a signal laser; and output an optical beam. Each photodiode may be configured to: receive at least a portion of the optical beam and at least a portion of an optical plane wave beam, wherein the optical plane wave beam is formed based at least on a local oscillator (LO) laser that outputs a laser beam having a different wavelength from the signal laser; and output an electronic signal based on the at least the portion of the optical beam and the at least a portion of the optical plane wave beam. The RF antenna element array may be configured to output an RF beam based on received electronic signals from the photodiode array.

An example radar system includes a transmission array and a reception array, each aligned as a linear array. The radar system also includes a transmitter configured to cause transmission of radar signals having a center frequency by the transmission array. The radar system also includes a receiver configured to receive radar signals having the center frequency that are received by the reception array. The radar system also includes a processor configured to process received radar signals from the receiver, and adjust the center frequency from a first center frequency to a second center frequency. The adjusting of the center frequency from the first center frequency to the second center frequency causes the frequency-dependent transmission radiation pattern of the transmission array to tilt in a first direction and the frequency-dependent reception radiation pattern of the reception array to tilt in an opposite direction from the first direction.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit, to a base station, a report indicating that a cooperative reception group including the UE and one or more other UEs connected to the UE over an out-of-band link supports one or more downlink transmit beamforming techniques. The UE may determine, based at least in part on the one or more downlink transmit beamforming techniques supported by the cooperative reception group, a downlink transmit precoder associated with relaxed beamforming nulling. The UE may decode a downlink transmission received from the base station based at least in part on the downlink transmit precoder and one or more decoded bits received from the one or more other UEs in the cooperative reception group. Numerous other aspects are provided.