A system for transmitting and receiving radio signals is disclosed. The system includes a controller having a modem and a transmission amplifier module connected to the modem, an antenna unit arranged at a distance from the controller and having an antenna and a reception amplifier module connected to the antenna, and a high-frequency cable connecting the controller and the antenna unit.

A radio frequency circuit includes: a first filter having a first passband that corresponds to a portion of a frequency range of a first communication band allocated as a communication band for TDD; a second filter having a second passband that corresponds to a portion of the frequency range of the first communication band, the second passband being different from the first passband; a power amplifier that amplifies a transmission signal in the first communication band; a low-noise amplifier that amplifies a reception signal in the first communication band; and a switch that switches between connecting the first filter and the power amplifier and connecting the first filter and the low-noise amplifier, and switches between connecting the second filter and the power amplifier and connecting the second filter and the low-noise amplifier.

A multiplexer includes first, second, and third filters with first, second, and third frequency bands different from each other, a first connection point connected to a common terminal, a second connection point connected to one end of the first filter and one end of the second filter, a first switch that switches connection and disconnection between the first and second connection points, a reactance element whose one end is connected to a signal path connecting the second connection point and the first switch, a second switch that switches connection and disconnection between the other end of the reactance element and the first connection point, and a third switch that switches connection and disconnection between one end of the third filter and the first connection point. The first and second frequency bands are adjacent to each other among the first, second, and third frequency bands.

A communication apparatus electrically connected to a first antenna through a first cable includes a second antenna that is substitutable for the first antenna; a first ground portion to which a second cable for grounding the first antenna is connected; an antenna detection circuit to detect a state of the first antenna; an antenna switching unit to switch from the first antenna to the second antenna, in a case where the antenna detection circuit detects an abnormality of the first antenna; and an insulating portion to insulate the first ground portion from a second ground portion around the first ground portion, in a case where the antenna detection circuit detects an abnormality of the first antenna.

Systems and methods are described for paired-beam satellite communications in a flexible satellite architecture. Embodiments include one or more bent pipe satellites having multiple transponders for servicing a number of spot beams. Implementations include novel types of paired-beam transponders that communicatively couple gateway terminals and user terminals in different spot beams. Some implementations also include loopback transponders that communicatively couple gateway terminals and user terminals in the same spot beam. The transponders can use similar components, can provide for flexible forward-link and return-link spectrum allocation, and/or can provide other features. Certain embodiments further include support for utility gateway terminal service and/or redundancy (e.g., active spares) for one or more active components.

Systems and methods are described for paired-beam satellite communications in a flexible satellite architecture. Embodiments include one or more bent pipe satellites having multiple transponders for servicing a number of spot beams. Implementations include novel types of paired-beam transponders that communicatively couple gateway terminals and user terminals in different spot beams. Some implementations also include loopback transponders that communicatively couple gateway terminals and user terminals in the same spot beam. The transponders can use similar components, can provide for flexible forward-link and return-link spectrum allocation, and/or can provide other features. Certain embodiments further include support for utility gateway terminal service and/or redundancy (e.g., active spares) for one or more active components.

A communication apparatus electrically connected to a first antenna through a first cable includes a second antenna that is substitutable for the first antenna; a first ground portion to which a second cable for grounding the first antenna is connected; an antenna detection circuit to detect a state of the first antenna; an antenna switching unit to switch from the first antenna to the second antenna, in a case where the antenna detection circuit detects an abnormality of the first antenna; and an insulating portion to insulate the first ground portion from a second ground portion around the first ground portion, in a case where the antenna detection circuit detects an abnormality of the first antenna.

A low frequency (LF) antenna control circuit is disclosed. The LF antenna control circuit includes an antenna driver to drive an antenna, a current and phase measurement circuit to measure antenna current and signal phase, a modulator to modulate a signal to be transmitted via the antenna and a controller configured to drive the antenna through the antenna driver using a first fixed amplitude for a first time period, a second fixed amplitude for a second time period that is subsequent to the first time period and subsequent to the second time period, and subsequently, to drive the antenna using step up/down voltages based on the measured antenna current and signal phase. The signal included encoded bits of data to be transmitted.

A microwave backhaul system may comprise a monolithic integrated circuit comprising an on-chip transceiver, digital baseband processing circuitry, and auxiliary interface circuitry. The on-chip transceiver may process a microwave signal from an antenna element to generate a first pair of quadrature baseband signals and convey the first pair of phase-quadrature baseband signals to the digital baseband processing circuitry. The auxiliary interface circuitry may receive one or more auxiliary signals from a source that is external to the monolithic integrated circuit and convey the one or more auxiliary signals to the digital baseband processing circuitry. The digital baseband processing circuitry may be operable to process signals to generate one or more second pairs of phase-quadrature digital baseband signals.

A transceiver having a down-converter for converting a radio-frequency (RF) input signal to an intermediate frequency (IF) signal with an analog low latency bypass path coupled to the IF signal and configured to provide a low latency IF signal and an up-converter for converting an IF signal to an RF signal. There is a digital path coupled to the IF signal and configured to provide a digitally processed IF signal, and an up-converter for converting at least one of the low latency IF signal and the digitally processed IF signal to an RF output signal. In a further example, the down-converter and the up-converter convert to millimeter wave frequencies and filters the millimeter wave frequencies with cavity filters.