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.