A remote antenna unit including at least one antenna configured to enable conversion between a digital signal and a radio signal; an external digital interface for providing the digital signal; and means for adapting performance of the antenna in dependence upon measurement of at least one parameter.

A transmitting circuit. In some embodiment, the transmitting circuit includes a slot antenna and an amplifier. The slot antenna may include a slot in a conductive sheet, and it may have a first resonant frequency, the first resonant frequency being within 20% of a slot frequency which is between a first frequency corresponding, in a first volume, to a wavelength twice the length of the slot, and a second frequency corresponding, in a second volume, to a wavelength twice the length of the slot. The amplifier may be connected to the slot through a connection including a conductive path, between the amplifier and the slot, having a length less than 0.2 times the length of the slot. The magnitude of the output impedance of the amplifier may be less than 0.25 times the magnitude of the impedance of the slot antenna at a first resonant frequency.

A transmitting circuit. In some embodiment, the transmitting circuit includes a slot antenna and an amplifier. The slot antenna may include a slot in a conductive sheet, and it may have a first resonant frequency, the first resonant frequency being within 20% of a slot frequency which is between a first frequency corresponding, in a first volume, to a wavelength twice the length of the slot, and a second frequency corresponding, in a second volume, to a wavelength twice the length of the slot. The amplifier may be connected to the slot through a connection including a conductive path, between the amplifier and the slot, having a length less than 0.2 times the length of the slot. The magnitude of the output impedance of the amplifier may be less than 0.25 times the magnitude of the impedance of the slot antenna at a first resonant frequency.

According to an embodiment, an antenna includes a conductive antenna element, a voltage-bias conductor, and a polarization-compensation conductor. The conductive antenna element is configured to radiate a first signal having a first polarization, and the voltage-bias conductor is coupled to a side of the antenna element and is configured to radiate a second signal having a second polarization that is different from the first polarization. And the polarization-compensating conductor is coupled to an opposite side of the antenna element and is configured to radiate third a signal having a third polarization that is approximately the same as the second polarization and that destructively interferes with the second signal. Such an antenna can be configured to reduce cross-polarization of the signals that its antenna elements radiate.

A system for EMNZ metamaterial-based direct antenna modulation. The system includes a signal generator, a metamaterial switch and an antenna. The signal generator may is configured to generate a microwave signal. The metamaterial switch is configured to generate a modulated microwave signal from the microwave signal. The modulated microwave signal is generated by selectively passing the microwave signal through the metamaterial switch. The metamaterial switch includes a first conductive plate and a first loaded conductive plate. The first loaded conductive plate includes a second conductive plate and a first monolayer graphene. The first monolayer graphene includes a first tunable conductivity. The first monolayer graphene is positioned between the first conductive plate and the second conductive plate. An effective permittivity of the metamaterial switch is configured to be adjusted to a predetermined value. The effective permittivity of the metamaterial switch is adjusted responsive to tuning the first tunable conductivity.

An RFID tag is disclosed comprising a dielectric substrate having a first side and an opposite second side, and with an antenna arranged on the first side of the dielectric substrate. The antenna defines a gap and is configured to operate at an operation frequency. The RFID tag further comprises an RFID chip electrically coupled to the antenna across the gap. A shielding conductor is arranged on the second side of the dielectric substrate, and preferably underlaying the gap, wherein the shielding conductor is configured to limit the voltage across the gap when the antenna is exposed to a microwave frequency of a microwave oven.

An antenna module includes a connection member, an integrated circuit (IC) on a first surface thereof, and an antenna package on a second surface thereof. The connection member includes a wiring layer and an insulating layer. The IC is electrically connected to the wiring layer. The antenna package includes first antenna members and feed vias each electrically connected to a corresponding one of the first antenna members and a corresponding wire of the wiring layer. A feed line is electrically connected to a wire of the wiring layer and extends in a side direction of the second surface, a second antenna member is electrically connected to the feed line and is configured to transmit and/or receive an RF signal in the side direction, and a director member is spaced apart from the second antenna member in the side direction and has an inside boundary oblique to the second antenna member.

An antenna array may include a plurality of printed circuit boards (PCBs) oriented in a stacked arrangement, parallel to and spaced apart from one another. Each of the PCBs may include a linear array of antenna elements, which cooperate with the linear arrays of antenna elements on other PCBs to form a two-dimensional array of antenna elements. The PCBs may be supported at one end by a common backplate in a cantilevered manner, with the linear arrays of antenna elements located near the free end of the PCBs. The PCBs may include a thicker portion and a thinner portion, and the thinner portion may include a heat sink or other thermal dissipation structure.

A dipole antenna fed by a planar balun includes a first radiation element and a second radiation element respectively corresponding to poles of the dipole antenna, at least one dipole support column configured to connect the first radiation element and the second radiation element and to fix a gap between the first radiation element and the second radiation element, a planar balun connected to the first radiation element and the second radiation element and configured to feed the first radiation element and the second radiation element, and a balun housing coupled to the dipole support column and enclosing the planar balun.

Radiating elements of first and second linear arrays of radiating elements have respective feed stalks that can reside at an angle to provide a balanced dipole arm with an inner end portion laterally offset to be closer to a right or left side of the base station antenna and reflector than an outer end portion that faces a radome of the base station antenna. The feed stalk can include sheet metal legs and printed circuit boards providing an RF transmission line(s).