A modular feed system for axis symmetric reflector antennas includes an upper hat segment, a mid-section segment and a lower base segment, the upper hat and lower base segments being securable to respective opposing ends of the mid-section segment; wherein the length of the mid-section segment is selected in order to accommodate application of a particularly sized reflector antenna; and a mechanical mating mechanism including base slots for feed spring entry, corresponding carriage springs on the feed, and corresponding recessed spring capture locations; and wherein the carriage springs are sized and configured to pass through the corresponding base slots for feed spring entry as part of the initial mating of the feed to the base segment, and selective rotation thereof moves the corresponding carriage springs into corresponding recessed spring capture locations and causing a mechanically audible sound for indicating that the feed has locked into position.

In various implementations, a quasi-monostatic STAR antenna system comprises a parabolic reflector antenna for transmission (TX) and a receiving (RX) antenna mounted back-to-back with the reflector feed. The physical size of the RX antenna can be comparable to or smaller than that of the TX feed, in order to prevent additional reflector blockage. To increase the system isolation both the TX feed and the RX antenna are CP. In one implementation, for example, to achieve same TX and RX polarization (i.e. no polarization multiplexing) the TX feed is LHCP and the RX antenna is RHCP. The LHCP fields from the TX feed undergo polarization reversal after bouncing back from the reflector. Thereby, the TX and RX operate in the same polarization, as illustrated in FIG. 1. This approach can also support simultaneous dual polarized operation if appropriate feed and RX antenna are used

In various implementations, a quasi-monostatic STAR antenna system comprises a parabolic reflector antenna for transmission (TX) and a receiving (RX) antenna mounted back-to-back with the reflector feed. The physical size of the RX antenna can be comparable to or smaller than that of the TX feed, in order to prevent additional reflector blockage. To increase the system isolation both the TX feed and the RX antenna are CP. In one implementation, for example, to achieve same TX and RX polarization (i.e. no polarization multiplexing) the TX feed is LHCP and the RX antenna is RHCP. The LHCP fields from the TX feed undergo polarization reversal after bouncing back from the reflector. Thereby, the TX and RX operate in the same polarization, as illustrated in FIG. 1. This approach can also support simultaneous dual polarized operation if appropriate feed and RX antenna are used

At least one embodiment of the present invention includes an antenna system comprising a multifocal reflector having at least two reflecting segments having different curvatures defining at least two different spaced apart focal points, such that the multifocal reflector is configured and operable to receive radiation incident on the segments at different incident angles within a certain angular range, and reflect the incident radiation onto the at least two focal points in a focal axis, thereby creating focused radiation formed by at least two differently focused portions of radiation; a phased array feed antenna unit located perpendicularly to the focal axis and comprising a plurality of antenna elements for receiving/transmitting at least two differently focused portions, and a feed network connected to the plurality of the antenna elements for selectively actuating the antenna elements for performing electronic scanning of the space area aimed at detecting target.

The present disclosure aims to provide an antenna directivity adjustment apparatus and an antenna directivity adjustment method capable of preventing an antenna gain from being reduced and easily adjusting a direction of an antenna. An antenna directivity adjustment apparatus (1) includes: a second antenna (2) that is opposed to a radiation surface (100a) of a first antenna (100) and receives radio waves output from the first antenna (100); and an output unit (3) that is provided in the second antenna (2), converts a first beam width of the received radio waves into a second beam width wider than the first beam width, and outputs the radio waves having the second beam width.

Systems and methods are provided for separating the uplink signal from the downlink signal in a satellite communication system. A communication terminal for satellite communications is provided, comprising a reflector having a prime focus; a first feed located at the prime focus of the reflector and in optical communication with the reflector; a frequency-selective surface module having a reflected focus and located at a point along a communication path between the main reflector and the first feed; and a second feed located at the reflected focus of the frequency-selective surface module and in optical communication with the frequency-selective surface module.

An antenna device includes: a first antenna that is provided on a board and forms a main lobe in a first direction along a plane of the board; a second antenna that is provided on the board and forms a main lobe in a second direction along the plane of the board, the second direction forming an angle of greater than 90 degrees and equal to or less than 180 degrees with respect to the first direction; a first reflecting mirror that changes a traveling direction of radio waves radiated in the first direction from the first antenna into a third direction; and a second reflecting mirror that changes a traveling direction of radio waves entering from a fourth direction into the second direction.

An antenna device includes: a first antenna that is provided on a board and forms a main lobe in a first direction along a plane of the board; a second antenna that is provided on the board and forms a main lobe in a second direction along the plane of the board, the second direction forming an angle of greater than 90 degrees and equal to or less than 180 degrees with respect to the first direction; a first reflecting mirror that changes a traveling direction of radio waves radiated in the first direction from the first antenna into a third direction; and a second reflecting mirror that changes a traveling direction of radio waves entering from a fourth direction into the second direction.

A reflector antenna includes: a radiator that radiates a radio wave; a main reflector that reflects the radio wave radiated from the radiator in a communication direction; an expansion panel that is attached to at least a part of the main reflector to increase an area of the main reflector; and a first adjustment unit that changes a position of the radiator, or a second adjustment unit that replaces the radiator with a radiator having a different radiation angle. This configuration makes it possible to implement a large-aperture antenna having excellent transportability and operability without preparing another antenna having a large aperture and replacing a standard antenna.

An antenna device, for a mobile body, of this disclosure includes an antenna configured to be installed in the mobile body, and a reflector having a reflection surface configured to change a beam direction of the antenna.