Abstract: A broadband quadruple helical circularly-polarized antenna for receiving GNSS signals comprises an excitation circuit and a set of quadruple spiral elements. Each quadruple spiral element consists of four conductors. Each conductor is a one spiral turn of the quadruple spiral element. Said conductors have equal winding angle. The winding angle of all conductors does not change in the same quadruple spiral element. Conductors of neighboring (longitudinally) quadruple spiral elements have different winding angles. The antenna provides a sharp drop in AP at angles near the horizon and a small AP level in the lower hemisphere.

Abstract: A broadband quadruple helical circularly-polarized antenna for receiving circularly polarized GNSS signals includes a dielectric cylinder oriented along a vertical axis; four spiral conductors wrapped around the cylinder; the four spiral conductors divided into an upper longitudinal section and a lower longitudinal section; and inductors connecting corresponding spiral conductors of the top and lower longitudinal sections. The spiral conductors in each section have a constant winding angle around the cylinder. The winding angle of all of the conductors in the same longitudinal section is the same. The winding angle of the upper longitudinal section is smaller than the winding angle of the bottom longitudinal. An excitation circuit is connected to the conductors. A third longitudinal section is below the lower longitudinal section, wherein the third longitudinal section includes conductors wound in an opposite direction relative to the lower longitudinal section.

Abstract: An antenna system for a global navigation satellite system reference base station is disclosed. The antenna system includes an antenna positioned above a high capacitive impedance surface (HCIS) ground plane. Over a specific range of the lateral dimension of the HCIS ground plane and the height of the antenna above the HCIS ground plane, a high level of multipath suppression and high sensitivity for low-elevated satellites can be simultaneously maintained. The HCIS ground plane can be fabricated as a flat conducting plate with an array of conducting elements such as pins, pins with expanded tips, or mushroom structures. Alternatively, the HCIS can be fabricated as a flat conducting plate with a concentric series of choke rings. The antenna system can provide a positioning accuracy of +/?1 mm, an order of magnitude improvement over previous designs.

Abstract: A broadband quadruple helical circularly-polarized antenna for receiving GNSS signals comprises an excitation circuit and a set of quadruple spiral elements. Each quadruple spiral element consists of four conductors. Each conductor is a one spiral turn of the quadruple spiral element. Said conductors have equal winding angle. The winding angle of all conductors does not change in the same quadruple spiral element. Conductors of neighboring (longitudinally) quadruple spiral elements have different winding angles. The antenna provides a sharp drop in AP at angles near the horizon and a small AP level in the lower hemisphere.

Abstract: An antenna system for a global navigation satellite system reference base station is disclosed. The antenna system includes an antenna positioned above a high capacitive impedance surface (HCIS) ground plane. Over a specific range of the lateral dimension of the HCIS ground plane and the height of the antenna above the HCIS ground plane, a high level of multipath suppression and high sensitivity for low-elevated satellites can be simultaneously maintained. The HCIS ground plane can be fabricated as a flat conducting plate with an array of conducting elements such as pins, pins with expanded tips, or mushroom structures. Alternatively, the HCIS can be fabricated as a flat conducting plate with a concentric series of choke rings. The antenna system can provide a positioning accuracy of +/?1 mm, an order of magnitude improvement over previous designs.

Abstract: An antenna system with a sharp difference in directional pattern is intended for receiving GNSS signals. The antenna system includes at least two antenna elements located above a high-impedance capacitive ground plane, and a combining network. Antenna elements are spaced apart in vertical direction. The combining network provides subtraction of the signal reflected from the ground, the arrangement of antenna elements above the high-impedance capacitive ground plane making such subtraction efficient.

Abstract: Disclosed is a dual-band Global Navigation Satellite System antenna with a hollow core. The antenna includes a conductive cylindrical tube with a longitudinal axis. A ground plane, a low-frequency radiator, and a high-frequency radiator are annuli orthogonal to the longitudinal axis. The inner peripheries of the ground plane and the low-frequency radiator are electrically connected to the outer surface of the cylindrical tube. The outer periphery of the high-frequency radiator is electrically connected to the low-frequency radiator. A vertical low-frequency radiating gap is configured between the ground plane and the outer periphery of the low-frequency radiator. A horizontal high-frequency radiating gap is configured between the inner periphery of the high-frequency radiator and the outer surface of the cylindrical tube. In an embodiment, the inner diameter of the cylindrical tube has a value from about 27 mm to about 102 mm, permitting insertion of a post or pole.

Abstract: An antenna is configured to operate with circularly-polarized electromagnetic radiation in a low-frequency band and in a high-frequency band. The antenna comprises a ground plane and a radiator. The radiator comprises four pairs of radiating elements disposed as pairs of spiral segments on a cylindrical surface having a longitudinal axis orthogonal to the ground plane. Each pair of radiating elements comprises a low-frequency radiating element and a high-frequency radiating element. The low-frequency radiating element comprises a low-frequency conductive strip. The high-frequency radiating element comprises an electrically-connected series of at least one high-frequency conductive strip and at least one high-frequency capacitor. The electrical path lengths of the low-frequency radiating elements and the electrical path lengths of the high-frequency radiating elements are equal.

Abstract: An antenna system includes an electromagnetic radiator assembled on a ground plane. The ground plane containing a nontransparent area in a center of the ground plane and a semitransparent area surrounding the nontransparent area. The nontransparent area is circular in shape. The semitransparent area is generally circular in shape and contains at least one slot. A plurality of vertical conducting elements are in proximity of a boundary between the nontransparent area and the semitransparent area on a bottom side of the ground plane. The vertical conducting elements are arranged in a circle around a center of the electromagnetic radiator.

Abstract: A compact GNSS antenna system reduces directional diagram level in the rear hemisphere primarily for LHCP component. It can be used for reducing multipath reception. A dual-band antenna system for receiving radio signals includes an active Microstrip Patch (MP) High Frequency (HF) circularly-polarized radiator disposed directly on a radiating patch of an active MP low-frequency (LF) radiator. The radiating patch of the active MP LF radiator serves as a ground plane of the MP HF radiator. A loop HF radiator is coaxially arranged around the ground plane of the MP HF radiator. A passive LF radiator is under the ground plane of the active MP LF radiator. A loop LF radiator is axially located around the ground plane of the active MP LF radiator. The loop HF radiator and the loop LF radiator are each excited by a transmission line and a power circuit to generate RHCP waves.

Abstract: An antenna system with a sharp difference in directional pattern is intended for receiving GNSS signals. The antenna system includes at least two antenna elements located above a high-impedance capacitive ground plane, and a combining network. Antenna elements are spaced apart in vertical direction. The combining network provides subtraction of the signal reflected from the ground, the arrangement of antenna elements above the high-impedance capacitive ground plane making such subtraction efficient.

Abstract: A compact GNSS antenna system reduces directional diagram level in the rear hemisphere primarily for LHCP component. It can be used for reducing multipath reception. A dual-band antenna system for receiving radio signals includes an active Microstip Patch (MP) High Frequency (HF) circularly-polarized radiator disposed directly on a radiating patch of an active MP low-frequency (LF) radiator. The radiating patch of the active MP LF radiator serves as a ground plane of the MP HF radiator. A loop HF radiator is coaxially arranged around the ground plane of the MP HF radiator. A passive LF radiator is under the ground plane of the active MP LF radiator. A loop LF radiator is axially located around the ground plane of the active MP LF radiator. The loop HF radiator and the loop LF radiator are each excited by a transmission line and a power circuit to generate RHCP waves.

Abstract: Disclosed is a dual-band Global Navigation Satellite System antenna with a hollow core. The antenna includes a conductive cylindrical tube with a longitudinal axis. A ground plane, a low-frequency radiator, and a high-frequency radiator are annuli orthogonal to the longitudinal axis. The inner peripheries of the ground plane and the low-frequency radiator are electrically connected to the outer surface of the cylindrical tube. The outer periphery of the high-frequency radiator is electrically connected to the low-frequency radiator. A vertical low-frequency radiating gap is configured between the ground plane and the outer periphery of the low-frequency radiator. A horizontal high-frequency radiating gap is configured between the inner periphery of the high-frequency radiator and the outer surface of the cylindrical tube. In an embodiment, the inner diameter of the cylindrical tube has a value from about 27 mm to about 102 mm, permitting insertion of a post or pole.

Abstract: An antenna system for global navigation satellite systems includes a ground plane, an active antenna disposed above the ground plane, and a passive antenna disposed below the ground plane. The active antenna includes a conducting ring substantially parallel to the ground plane. A radiating conductor passes through substantially the center of the conducting ring; the ends of the radiating conductor are electrically connected to the conducting ring. An excitation pin is electrically connected to the radiating conductor. A set of reactive impedance elements is electrically connected between the conducting ring and the ground plane. The set of reactive impedance elements is disposed substantially orthogonal to the ground plane. The passive antenna is similar to the active antenna, except the passive antenna does not have an excitation pin. The antenna system effectively suppresses multipath reception, and its compact size and light weight make it suitable for integration with a surveying pole.

Abstract: An antenna is configured to operate with circularly-polarized electromagnetic radiation in a low-frequency band and in a high-frequency band. The antenna comprises a ground plane and a radiator. The radiator comprises four pairs of radiating elements disposed as pairs of spiral segments on a cylindrical surface having a longitudinal axis orthogonal to the ground plane. Each pair of radiating elements comprises a low-frequency radiating element and a high-frequency radiating element. The low-frequency radiating element comprises a low-frequency conductive strip. The high-frequency radiating element comprises an electrically-connected series of at least one high-frequency conductive strip and at least one high-frequency capacitor. The electrical path lengths of the low-frequency radiating elements and the electrical path lengths of the high-frequency radiating elements are equal.

Abstract: Patch antennas for signals of global navigation satellite systems (GNSS) are described. A compact antenna system reduces directional diagram level in the rear hemisphere primarily for cross-polarized (left hand circularly-polarized) component. It can be used for reducing multipath reception. The antenna receives GNSS signals and includes a patch circularly-polarized radiator consisting of a radiating patch, a ground plane under it and a loop radiator coaxially located around the patch radiator. The loop radiator is excited by a separate power circuit or by a passive method where LHCP waves of MP and loop radiators in the rear hemisphere would be anti-phase added. A dual-band antenna system includes an active HF radiator, under which there is an active LF radiator under which there is a passive LF radiator, a loop HF radiator being coaxially located around the active HF radiator.

Abstract: An antenna system for global navigation satellite systems includes a ground plane, an active antenna disposed above the ground plane, and a passive antenna disposed below the ground plane. The active antenna includes a conducting ring substantially parallel to the ground plane. A radiating conductor passes through substantially the center of the conducting ring; the ends of the radiating conductor are electrically connected to the conducting ring. An excitation pin is electrically connected to the radiating conductor. A set of reactive impedance elements is electrically connected between the conducting ring and the ground plane. The set of reactive impedance elements is disposed substantially orthogonal to the ground plane. The passive antenna is similar to the active antenna, except the passive antenna does not have an excitation pin. The antenna system effectively suppresses multipath reception, and its compact size and light weight make it suitable for integration with a surveying pole.

Abstract: Patch antennas for signals of global navigation satellite systems (GNSS) are described. A compact antenna system reduces directional diagram level in the rear hemisphere primarily for cross-polarized (left hand circularly-polarized) component. It can be used for reducing multipath reception. The antenna receives GNSS signals and includes a patch circularly-polarized radiator consisting of a radiating patch, a ground plane under it and a loop radiator coaxially located around the patch radiator. The loop radiator is excited by a separate power circuit or by a passive method where LHCP waves of MP and loop radiators in the rear hemisphere would be anti-phase added. A dual-band antenna system includes an active HF radiator, under which there is an active LF radiator under which there is a passive LF radiator, a loop HF radiator being coaxially located around the active HF radiator.