A liquid crystal antenna unit and a liquid crystal phased array antenna are provided. The liquid crystal antenna unit includes: a first substrate, a second substrate opposite to the first substrate, a liquid crystal layer between the first substrate and the second substrate, a transmission line on a first surface and extending in a first direction along the first surface, a first antenna oscillator on the first surface and arranged as an elongated dipole extending in a second direction along the first surface, a second antenna oscillator on a surface of the second substrate distal to the first substrate and at a position corresponding to the first antenna oscillator, and a ground electrode on a surface of the first substrate distal to the second substrate.

Dipole antenna arrays are disclosed. An example dipole antenna array includes a ground plane having a first serrated edge, and a first dipole antenna, at least a portion of the first dipole antenna disposed parallel to the first serrated edge.

Dipole antenna arrays are disclosed. An example dipole antenna array includes a ground plane having a first serrated edge, and a first dipole antenna, at least a portion of the first dipole antenna disposed parallel to the first serrated edge.

A communications system is described which comprises a transmission unit including a transmission circuit 12 operable to output a transmission signal to a ground antenna 22 driven, in use, into a ground formation, and an impedance adjusting unit 20 electrically connected between the transmission circuit 12 and the antenna 22 and operable to adjust the transmission output impedance. A ground antenna 22 is also described comprising a single rod or stake including a first active section 30, a second active section 32 spaced apart from the first section 30 and collinear or coaxial therewith, and an insulating section 34 located between the first and second sections 30, 32, holding the first and second sections 30, 32 in a spaced, collinear or coaxial relationship.

A communications system is described which comprises a transmission unit including a transmission circuit 12 operable to output a transmission signal to a ground antenna 22 driven, in use, into a ground formation, and an impedance adjusting unit 20 electrically connected between the transmission circuit 12 and the antenna 22 and operable to adjust the transmission output impedance. A ground antenna 22 is also described comprising a single rod or stake including a first active section 30, a second active section 32 spaced apart from the first section 30 and collinear or coaxial therewith, and an insulating section 34 located between the first and second sections 30, 32, holding the first and second sections 30, 32 in a spaced, collinear or coaxial relationship.

A dual-feed dual-band multiple-input and multiple-output (MIMO) antenna apparatus includes an antenna radiator, a first feed port, a second feed port, a first filter unit, and a second filter unit. The first feed port and the second feed port are spaced on the antenna radiator in a length direction of the antenna radiator. The first filter unit is disposed between the first feed port and the antenna radiator, and the second filter unit is disposed between the second feed port and the antenna radiator. The first filter unit is configured to pass a frequency component within a first preset frequency range, and filter out a frequency component outside the first preset frequency range; and the second filter unit is configured to filter out a frequency component within a second preset frequency range, and pass a frequency component outside the second preset frequency range.

An RFID tag is provided for transmitting and receiving a communication signal. The RFID tag includes a base material, an antenna pattern disposed on the base material, and a high-loss member. The high-loss member is disposed adjacent to the antenna pattern and has a high loss at a frequency higher than a frequency of the communication signal, compared with the antenna pattern and the base material. When the RFID tag is subjected to an electromagnetic wave heating microwave, the high-loss member generates heat and the antenna pattern is cut at a position of the high-loss member.

This application provides a radiating element, an antenna array, and a network device, to avoid mutual shielding between dipoles during multi-band transmission, and therefore improve radiation performance. The radiating element includes one or more dipoles and a supporter. The one or more dipoles are suspended on the top of the supporter, and each of the one or more dipoles is connected to the supporter at a specific angle. A dipole arm of each dipole is covered with a periodic structure. The periodic structure is configured to enable an electromagnetic wave radiated to a first surface of each dipole to be incident to a second surface of each dipole, where the first surface and the second surface are any two opposite surfaces of each dipole.

This application provides a radiating element, an antenna array, and a network device, to avoid mutual shielding between dipoles during multi-band transmission, and therefore improve radiation performance. The radiating element includes one or more dipoles and a supporter. The one or more dipoles are suspended on the top of the supporter, and each of the one or more dipoles is connected to the supporter at a specific angle. A dipole arm of each dipole is covered with a periodic structure. The periodic structure is configured to enable an electromagnetic wave radiated to a first surface of each dipole to be incident to a second surface of each dipole, where the first surface and the second surface are any two opposite surfaces of each dipole.

An omni-directional horizontally polarized antenna system is provided that can include an omni-directional vertically polarized antenna and a plurality of linear polarization filters concentrically surrounding the omni-directional vertically polarized antenna. The omni-directional vertically polarized antenna can generate a vertically polarized field, and the plurality of linear polarization filters can progressively rotate the vertically polarized field 90° to form a horizontally polarized field outside of the plurality of linear polarization filters.