A simple multi-directional, multi-port array antenna structure is disclosed that can be used for a variety of applications, including but not limited to direction finding (DF) and beam-forming applications in receive and transmit modes, respectively. The disclosed antenna structure offers unique functionalities in both receive and transmit modes. For DF applications in the receive mode, the back-end of the antenna structure features a power sensing mechanism to monitor the power received at all ports. In the transmit mode, the disclosed antenna structure is used for beamforming applications by providing individual port excitation and using antenna arrays.

OFDM-BPSK symbol sequences are used for mutual-coupling based phase array calibration. Such substitution allows phase to be estimated more accurately using a given estimation duration without compromising other estimates' (amplitude and group delay) accuracies.

A direction-finding antenna includes at least a first set of radiating elements configured to radiate at least a first wavelength (λ.sub.1) and a second set of radiating elements configured to radiate at a second wavelength (λ.sub.2) that is shorter than the first wavelength (λ.sub.1). The first set of radiating elements defines a first circle having a first radius. The second set of radiating elements defines a second circle having a second radius that is smaller than the first radius of the first circle. The direction-finding antenna further includes a transmission line-based multiplexer configured to selectively couple the first set of radiating elements or the second set of radiating elements to a radio frequency (RF) feed line, or a plurality of switches configured to selectively couple selected radiating elements of the first set of radiating elements or the second set of radiating elements to the RF feed line.

Apparatus for transmitting and/or receiving radio frequency, RF, signals, particularly for a mobile radio device for a wireless communications system, particularly a cellular communications system, said apparatus comprising a primary antenna module having a first radiation pattern, at least one secondary antenna module having a second radiation pattern, which is different from said first radiation pattern, and a control unit configured to selectively activate and/or deactivate said primary antenna module and/or said at least one secondary antenna module.

Methods and systems for shaping an electromagnetic wavefront are disclosed. A disclosed method includes tuning a tunable surface in an electromagnetic cavity and receiving the electromagnetic wavefront in the electromagnetic cavity. The electromagnetic wavefront includes a first wave defined by a first wavelength and a second wave defined by a second wavelength. The first wave and the second wave have a shared phase and a shared beam direction in the electromagnetic wavefront. The method further includes reflecting the electromagnetic wavefront within the cavity to repeatedly interact with the tunable surface, and transmitting, after reflecting the electromagnetic wavefront within the cavity, the electromagnetic wavefront from the electromagnetic cavity as a shaped electromagnetic wavefront. The first wave and the second wave have at least one of a difference in phase or a difference in beam direction in the shaped electromagnetic wavefront.

A transmission system and method for transmitting radio frequency (RF) radiation in a predetermined direction at a sequence of K frequencies by an antenna array. The system includes an RF signal generator configured for generating electrical signals having an initial amplitude and an initial phase through transmission channels corresponding to antenna elements of the antenna array at the sequence of K frequencies. The system also includes a modification system, configured for obtaining optimal electrical signals for which a transmission efficiency coefficient of the transmission system is equal to or greater than a predetermined threshold value, and a steering system configured for (i) receiving the optimal electrical signals, (ii) generating steering electrical signals related to the optimal electrical signals and (iii) relaying the steering electrical signals to the antenna array to form a steered beam for transmission in the predetermined direction.

OFDM-BPSK symbol sequences are used for mutual-coupling based phase array calibration. Such substitution allows phase to be estimated more accurately using a given estimation duration without compromising other estimates’ (amplitude and group delay) accuracies.

The apparatus may be a base station. The apparatus processes a first group of synchronization signals. The apparatus processes a second group of synchronization signals. The apparatus performs a first transmission by transmitting the processed first group of the synchronization signals in a first synchronization subframe. The apparatus performs a second transmission by transmitting the processed second group of the synchronization signals in a second synchronization subframe.

The phased array antenna system is described. The phased array antenna system formed on one or more layers of a printed circuit board (PCB). The phased array antenna system be may include a beam forming network to convert between one or more element signals and a beam signal. The phased array antenna system may include one or more control circuits, where each control circuit may receive the element signals for corresponding antenna element. Each of the control circuits may further may establish a control signal path and an element signal path between the antenna elements and the beamforming network, where the signal path may carry multiplexed element and control signals. The control circuits may include a signal adjustment circuit that may adjust the corresponding element signal (e.g., in phase or amplitude) based on the control signal.

A coupling device includes a plurality of couplers, a first coupled output port and a second coupled output port, wherein the plurality of couplers comprise a first coupler and a second coupler that are adjacent one another, and each of the first coupler and the second coupler comprises a main line and a subline, and for each of the first coupler and the second coupler: the subline includes a first section, a second section, and a third section, wherein the second section of the subline of the first coupler has a common segment with the first section of the subline of the second coupler.