Abstract: A downlink channel estimation method based on a co-prime array in asymmetric massive MIMO architecture is provided. First, an uplink and downlink asymmetric receiving and transmitting system model based on a co-prime array is established, and a deviation of the frequency domain direction caused by array broadband signals is observed; then, uplink receiving is performed to estimate an uplink channel, and channel parameters such as the number of paths, the angle of arrival and the path gain are recovered; and finally, a downlink channel is reconstructed based on the channel parameters recovered according to the uplink channel. By means of the high angular resolution of the co-prime array, the problem that a recovered uplink channel cannot be directly used for pre-coding of a downlink channel is solved.

Abstract: A downlink channel estimation method based on a co-prime array in asymmetric massive MIMO architecture is provided. First, an uplink and downlink asymmetric receiving and transmitting system model based on a co-prime array is established, and a deviation of the frequency domain direction caused by array broadband signals is observed; then, uplink receiving is performed to estimate an uplink channel, and channel parameters such as the number of paths, the angle of arrival and the path gain are recovered; and finally, a downlink channel is reconstructed based on the channel parameters recovered according to the uplink channel. By means of the high angular resolution of the co-prime array, the problem that a recovered uplink channel cannot be directly used for pre-coding of a downlink channel is solved.

Abstract: The present invention discloses a triple-resonant null frequency scanning antenna, which belongs to the technical fields of the Internet of Things and microwave. The triple-resonant null frequency scanning antenna comprises a circular sector magnetic dipole arranged on a medium substrate, and rectangular notches are symmetrically arranged on a sector patch of the circular sector magnetic dipole. The circular sector magnetic dipole is fixed on the medium substrate by a second shorting pin and third shorting pins, an flared angle of the circular sector magnetic dipole is a first central angle, and two third shorting pins are present and are symmetrically arranged on both sides of the angular bisector of the first central angle.

Abstract: The present invention discloses a sector dual-resonant dipole antenna. Radiation elements of the antenna are two identical sector patches. Two identical rectangular notches can be symmetrically arranged or two identical tuning stubs can be symmetrically loaded on the sector patches at positions deviating from the central axis of the two sector patches. Exciting points are symmetrically arranged on sides of the sector patches close to a central axis. The present invention realizes a wide beamwidth radiation characteristic through a two-dimensional sectorial resonator, and then the notches are arranged or the tuning stubs are loaded at appropriate positions of two arms of the sectorial resonator, and thereby a dual-resonant characteristic can be realized within a working band.

Abstract: A wide-beam planar backfire and bidirectional circularly-polarized antenna. An entire planar sectorial magnetic dipole is of a semi-closed structure, the planar sectorial magnetic dipole comprises two identical sectorial patches and a vertical short-circuit wall, and the vertical short-circuit wall is connected with straight sides of the two sectorial patches along a radial direction of the planar sectorial magnetic dipole; two sets of concentric annular electric dipoles are respectively used as a top concentric annular radiating element and a bottom concentric annular radiating element, as well as a top concentric annular reflector and a bottom anti-concentric annular reflector; and the top concentric annular radiating element is connected with an upper surface of the planar sectorial magnetic dipole through a top connecting branch, and the bottom concentric annular radiating element is connected with a lower surface of the planar sectorial magnetic dipole through a bottom connecting branch.

Abstract: The present invention discloses a sector dual-resonant dipole antenna. Radiation elements of the antenna are two identical sector patches. Two identical rectangular notches can be symmetrically arranged or two identical tuning stubs can be symmetrically loaded on the sector patches at positions deviating from the central axis of the two sector patches. Exciting points are symmetrically arranged on sides of the sector patches close to a central axis. The present invention realizes a wide beamwidth radiation characteristic through a two-dimensional sectorial resonator, and then the notches are arranged or the tuning stubs are loaded at appropriate positions of two arms of the sectorial resonator, and thereby a dual-resonant characteristic can be realized within a working band.

Abstract: The present invention discloses a triple-resonant null frequency scanning antenna, which belongs to the technical fields of the Internet of Things and microwave. The triple-resonant null frequency scanning antenna comprises a circular sector magnetic dipole arranged on a medium substrate, and rectangular notches are symmetrically arranged on a sector patch of the circular sector magnetic dipole. The circular sector magnetic dipole is fixed on the medium substrate by a second shorting pin and third shorting pins, an flared angle of the circular sector magnetic dipole is a first central angle, and two third shorting pins are present and are symmetrically arranged on both sides of the angular bisector of the first central angle.

Abstract: A wide-beam planar backfire and bidirectional circularly-polarized antenna. An entire planar sectorial magnetic dipole is of a semi-closed structure, the planar sectorial magnetic dipole comprises two identical sectorial patches and a vertical short-circuit wall, and the vertical short-circuit wall is connected with straight sides of the two sectorial patches along a radial direction of the planar sectorial magnetic dipole; two sets of concentric annular electric dipoles are respectively used as a top concentric annular radiating element and a bottom concentric annular radiating element, as well as a top concentric annular reflector and a bottom anti-concentric annular reflector; and the top concentric annular radiating element is connected with an upper surface of the planar sectorial magnetic dipole through a top connecting branch, and the bottom concentric annular radiating element is connected with a lower surface of the planar sectorial magnetic dipole through a bottom connecting branch.