Integrated antenna system
First Claim
1. An integrated quadrifilar helix antenna system for receiving and transmitting electromagnetic waves of wave length λ
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four spaced apart helical conductors wound in a common direction, the helical conductors defining a common central axis and helix antenna, the helical conductors each having a top end and a bottom end;
a first ground plane perpendicular to the central axis, the ground plane having a top surface and a bottom surface and a thickness therebetween, the first ground plane extending radially outward at least a preselected distance from the central axis beyond the bottom ends of the helical conductors;
conductive connections connecting the respective bottom ends of the helical conductors to the top surface of the first ground plane;
a dome enclosure having a proximal opening to receive the helical conductors and the conductive connections, the opening configured for mounting to the top surface of the ground plane;
a second ground plane having a second top surface and a second bottom surface and a thickness therebetween, the second ground plane mounted below the first ground plane, the first and second ground planes configured to define a first planar cavity between a recessed portion of the bottom surface of the first ground plane and a second planar cavity between a corresponding recessed portion of the top surface of the second ground plane, the periphery of the first and second ground planes configured to provide an electrically conductive connection surrounding the first and second cavities, the second ground plane providing an input port for transmitting RF signals in and out of the second cavity;
a signal feed having;
a) a signal transmission network having a first connection end and a second connection end, the first connection end for coupling RF signals to the top ends of the corresponding helical conductors, the second connection end passing through the first ground plane feedthrough opening;
b) a signal conditioning circuit including means for impedance matching and power splitting the RF signals to and from the transmission network, the signal conditioning circuit electrically connected to the second connection end of the signal transmission network, the signal conditioning circuit mounted parallel to the ground planes and inside the cavity;
a transmit/receive board having an upper and a lower surface and a thickness therebetween, the transmit/receive board including a low noise preamplifier means for amplifying RF signals from the signal conditioning circuit, the amplifier means having a predetermined gain and noise figure;
a conducting planar cover plate having an upper and a lower surface, the lower surface defining a base plane distal to the helix antenna, the upper surface of the cover plate defining a third cavity recessed from the upper surface of the cover plate, the third cavity configured to receive the transmit/receive circuit board, the circuit board mounted parallel to and spaced apart between the upper surface of the cover plate and the lower surface of the second ground plane, the cover plate mounted perpendicular to the central axis, the cover plate mounted below the second ground plane, the cover plate providing an axial bore therethrough;
a coaxial cable connector for connecting the amplified RF signals from the preamplifier means to a proximal end of a coaxial cable, the cable connector mounted below the lower surface of the transmit/receive board, the connector projecting axially through the cover plate axial bore;
in combination, the elevation and azimuthal gain profile of the helix antenna and the dome enclosure, the signal splitting and impedance matching of the signal conditioning circuit, the gain and noise figure of the preamplifier means each having predetermined characteristics, the antenna system defining an overall height between the top end of the enclosure and the cover plate base plane of about 127 mm;
the antenna system having a G/T profile as measured at the distal end of the coaxial cable, including up to 10 dB of cable loss between the cable distal end and the cable proximal end, which meets the SDM specification;
wherein the first and second ground planes provide a conducting shield between the helical conductors above the ground planes and other conducting elements located below the ground planes such that the cavity between the first and second ground planes providing a suitable containment structure for the signal conditioning circuit effectively isolating the circuit from the antenna helical conductors.
2 Assignments
0 Petitions
Accused Products
Abstract
Disclosed herein is a low profile quadrifilar helix antenna system having the non-fed ends of the helix conductor arms shorted to a first ground plane, the ground plane mounted below the helix. The first ground plane is mounted perpendicularly to the central axis of the helix and extends radially outward therefrom to form an effective electromagnetic shield between the helix and adjacent ground planes. The extension of the first ground plane combined with the shorted non-fed ends of the helix arms minimize the influence of placement of the antenna system near adjacent ground conductors on the VSWR performance of the antenna. The conical frustum geometry of the helix conductors is configured to provide a low profile, resonant antenna. An integrated signal conditioning network is mounted within a cavity defined between the first ground plane and a second ground plane below the first ground plane. The conductive elements of the network are thus shielded from influencing the radiation pattern of the antenna system. The perpendicular orientation of the electronics also provides an integrated antenna system having lower overall height. A refractive dielectric dome is provided enclosing the helix and electronics. The dome thickness and dielectric constant are selected to provide increased gain for the antenna system at low elevation angles, i.e. near the horizon.
305 Citations
4 Claims
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1. An integrated quadrifilar helix antenna system for receiving and transmitting electromagnetic waves of wave length λ
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four spaced apart helical conductors wound in a common direction, the helical conductors defining a common central axis and helix antenna, the helical conductors each having a top end and a bottom end; a first ground plane perpendicular to the central axis, the ground plane having a top surface and a bottom surface and a thickness therebetween, the first ground plane extending radially outward at least a preselected distance from the central axis beyond the bottom ends of the helical conductors; conductive connections connecting the respective bottom ends of the helical conductors to the top surface of the first ground plane; a dome enclosure having a proximal opening to receive the helical conductors and the conductive connections, the opening configured for mounting to the top surface of the ground plane; a second ground plane having a second top surface and a second bottom surface and a thickness therebetween, the second ground plane mounted below the first ground plane, the first and second ground planes configured to define a first planar cavity between a recessed portion of the bottom surface of the first ground plane and a second planar cavity between a corresponding recessed portion of the top surface of the second ground plane, the periphery of the first and second ground planes configured to provide an electrically conductive connection surrounding the first and second cavities, the second ground plane providing an input port for transmitting RF signals in and out of the second cavity; a signal feed having; a) a signal transmission network having a first connection end and a second connection end, the first connection end for coupling RF signals to the top ends of the corresponding helical conductors, the second connection end passing through the first ground plane feedthrough opening; b) a signal conditioning circuit including means for impedance matching and power splitting the RF signals to and from the transmission network, the signal conditioning circuit electrically connected to the second connection end of the signal transmission network, the signal conditioning circuit mounted parallel to the ground planes and inside the cavity; a transmit/receive board having an upper and a lower surface and a thickness therebetween, the transmit/receive board including a low noise preamplifier means for amplifying RF signals from the signal conditioning circuit, the amplifier means having a predetermined gain and noise figure; a conducting planar cover plate having an upper and a lower surface, the lower surface defining a base plane distal to the helix antenna, the upper surface of the cover plate defining a third cavity recessed from the upper surface of the cover plate, the third cavity configured to receive the transmit/receive circuit board, the circuit board mounted parallel to and spaced apart between the upper surface of the cover plate and the lower surface of the second ground plane, the cover plate mounted perpendicular to the central axis, the cover plate mounted below the second ground plane, the cover plate providing an axial bore therethrough; a coaxial cable connector for connecting the amplified RF signals from the preamplifier means to a proximal end of a coaxial cable, the cable connector mounted below the lower surface of the transmit/receive board, the connector projecting axially through the cover plate axial bore; in combination, the elevation and azimuthal gain profile of the helix antenna and the dome enclosure, the signal splitting and impedance matching of the signal conditioning circuit, the gain and noise figure of the preamplifier means each having predetermined characteristics, the antenna system defining an overall height between the top end of the enclosure and the cover plate base plane of about 127 mm; the antenna system having a G/T profile as measured at the distal end of the coaxial cable, including up to 10 dB of cable loss between the cable distal end and the cable proximal end, which meets the SDM specification; wherein the first and second ground planes provide a conducting shield between the helical conductors above the ground planes and other conducting elements located below the ground planes such that the cavity between the first and second ground planes providing a suitable containment structure for the signal conditioning circuit effectively isolating the circuit from the antenna helical conductors.
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2. An integrated quadrifilar helix antenna system for receiving and transmitting electromagnetic waves of wave length λ
- , comprising;
four spaced apart helical conductors wound in a common direction, the helical conductors defining a common central axis and helix antenna, the helical conductors each having a top end and a bottom end; a first ground plane perpendicular to the central axis, the ground plane having a top surface and a bottom surface and a thickness therebetween, the first ground plane extending radially outward at least a preselected distance from the central axis beyond the bottom ends of the helical conductors; conductive connections connecting the respective bottom ends of the helical conductors to the top surface of the first ground plane; a dome enclosure having a proximal opening to receive the helical conductors and the conductive connections, the opening configured for mounting to the top surface of the ground plane; a second ground plane having a second top surface and a second bottom surface and a thickness therebetween, the second ground plane mounted below the first ground plane, the first and second ground planes configured to define a first planar cavity between a recessed portion of the bottom surface of the first ground plane and a second planar cavity between a corresponding recessed portion of the top surface of the second ground plane, the periphery of the first and second ground planes configured to provide an electrically conductive connection surrounding the first and second cavities, the second ground plane providing an input port for transmitting RF signals in and out of the second cavity; a signal feed having; a) a signal transmission network having a first connection end and a second connection end, the first connection end for coupling RF signals to the top ends of the corresponding helical conductors, the second connection end passing through the first ground plane feedthrough opening; b) a signal conditioning circuit including means for impedance matching and power splitting the RF signals to and from the transmission network, the signal conditioning circuit electrically connected to the second connection end of the signal transmission network, the signal conditioning circuit mounted parallel to the ground planes and inside the cavity; c) the signal conditioning circuit having; a shorted suspended strip transmission line network for guiding the RF signals at a frequency f between an input and at least one output within the signal conditioning circuit, the strip line network comprising; two parallel ground planes defining a cavity therebetween; a planar dielectric sheet having a thickness, a dielectric constant, a top surface and a bottom surface, the sheet supported within the cavity, the sheet spaced apart from and between the two ground planes; a first conductive pattern including a first plurality of contiguous strip conductors formed on the top surface of the sheet; a second conductive pattern formed on the bottom surface of the sheet, the second pattern including a second plurality of contiguous strip conductors, the second plurality of conductors overlaying and essentially replicating the first pattern, thereby defining the strip transmission line network; the sheet defining a plurality of sequential spaced apart feedthrough holes along at least a portion of the strip transmission line network, the through holes successively separated by at most a maximum spacing distance d, the distance d arranged to be less than a pre-selected submultiple of the wavelength corresponding to the RF signal frequency f, each successive spaced apart through hole having a plated through conductor therethrough, each conductor electrically joining the corresponding first and second conductive patterns around the each through hole, thereby defining the shorted suspended substrate transmission line, wherein the RF signal impressed between the patterns and the ground planes will induce essentially zero RF electric field in the dielectric sheet between the overlaying first and second strip conductors thereby minimizing RF dielectric loss within the sheet, along the shorted suspended substrate transmission line; a transmit/receive board having an upper and a lower surface and a thickness therebetween, the transmit/receive board including a low noise preamplifier means for amplifying RF signals from the signal conditioning circuit, the amplifier means having a predetermined gain and noise figure; a conducting planar cover plate having an upper and a lower surface, the lower surface defining a base plane distal to the helix antenna, the upper surface of the cover plate defining a third cavity recessed from the upper surface of the cover plate, the third cavity configured to receive the transmit/receive circuit board, the circuit board mounted parallel to and spaced apart between the upper surface of the cover plate and the lower surface of the second ground plane, the cover plate mounted perpendicular to the central axis, the cover plate mounted below the second ground plane, the cover plate providing an axial bore therethrough; a coaxial cable connector for connecting the amplified RF signals from the preamplifier means to a proximal end of a coaxial cable, the cable connector mounted below the lower surface of the transmit/receive board, the connector projecting axially through the cover plate axial bore; the elevation and azimuthal gain profile of the helix antenna and the dome enclosure, in combination with the signal splitting and impedance matching of the signal conditioning circuit, the gain and noise figure of the preamplifier means each having predetermined characteristics; the first and second ground planes providing a conducting shield between the helix antenna conductors above the ground planes and other conducting elements located below the ground planes such that the cavity between the first and second ground planes providing a suitable containment structure for the signal conditioning circuit effectively isolating the circuit from the antenna helical conductors.
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3. An integrated quadrifilar helix antenna system comprising:
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four spaced apart helical conductors wound in a common direction, the helical conductors defining a common central axis, the helical conductors each having a top end and a bottom end; a ground plane perpendicular to the central axis, the ground plane having a top surface that is proximal to and below the bottom ends of the helical conductors, the ground plane extending radially outward at least a preselected distance from the central axis beyond the bottom ends of the helical conductors; conductive connections connecting the respective bottom ends of the helical conductors to the ground plane, wherein the ground plane provides a conducting shield for terminating electric field lines from the helical conductors; a signal feed that couples four balanced RF signals from the common central axis to the top ends of corresponding helical conductors, said signal feed having a shorted suspended strip transmission line network for guiding an RF signal at a frequency f between an input and the central axis, the strip line network including; a conductive plane spaced apart from and parallel to the ground plane defining a cavity therebetween; a planar dielectric sheet having a thickness, a dielectric constant, a top surface and a bottom surface, the sheet supported within the cavity, the sheet spaced apart from and between the conductive plane and the ground plane; a first conductive pattern including a first plurality of contiguous strip conductors formed on the top surface of the sheet; a second conductive pattern formed on the bottom surface of the sheet, the second pattern including a second plurality of contiguous strip conductors, the second plurality of conductors overlaying and essentially replicating the first pattern, thereby defining the strip transmission line network; the sheet defining a plurality of sequential spaced apart feedthrough holes along at least a portion of the strip transmission line network, the through holes successively separated by at most a maximum spacing distance d, the distance d arranged to be less than a pre-selective submultiple of the wavelength corresponding to the RF signal frequency f, each successive spaced apart through hole having a plated through conductor therethrough, each conductor electrically joining the corresponding first and second conductive patterns around the each through hole, thereby defining the shorted suspended substrate transmission line network, wherein the RF signal impressed between the patterns and the planes will induce essentially zero RF electric field in the dielectric sheet between the overlaying first and second strip conductors thereby minimizing RF dielectric loss within the sheet, along the shorted suspended substrate transmission line.
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4. An integrated quadrifilar helix antenna system comprising:
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four spaced apart helical conductors wound in a common direction, the helical conductors defining a common central axis, the helical conductors each having a top end and a bottom end; a ground plane perpendicular to the central axis, the ground plane having a top surface that is proximal to and below the bottom ends of the helical conductors, the ground plane extending radially outward at least a preselected distance from the central axis beyond the bottom ends of the helical conductors; conductive connections connecting the respective bottom ends of the helical conductors to the ground plane, wherein the ground plane provides a conducting shield for terminating electric field lines from the helical conductors; a signal feed that couples four balanced RF signals from the common central axis to the top ends of corresponding helical conductors, said signal feed having a suspended strip transmission line dual balun network for transforming two equi-amplitude, unbalanced, quadraphase RF signals at a wavelength λ
into a first and a second equi-amplitude, balanced, quadraphase RF output signals, including;a conductive plane spaced apart from and parallel to the ground plane defining a cavity therebetween; a planar dielectric sheet having a top surface and a bottom surface and a thickness therebetween, the sheet supported within the cavity, the sheet spaced apart from and parallel between the two planes; a first strip transmission line formed on the top surface of the sheet, the first line having an input end and an output end, and a first electrical length therebetween, providing a half wave phase shift between the input end and output end; a second strip transmission line formed on the bottom surface of the sheet, the second line having a second input end and a second output end and a second electrical length therebetween; a first pair of feedthroughs disposed on first diagonal corners of a quadrate equilateral, the feedthroughs penetrating the sheet therethrough, the equilateral defined in the plane of the sheet, the input end and output end of the first strip line each connected to a respective one of the first opposed pair of feedthroughs on the top surface of the sheet, the first pair of feedthroughs thereby defining the first balanced output signal; a second pair of feedthroughs disposed on opposed diagonal corners of the quadrate equilateral, the second pair of feedthroughs penetrating the thickness of the sheet therethrough, the input end and output end of the second strip line each connected to a respective one of the second opposed pair of feedthroughs on the bottom surface of the sheet; the second strip transmission line electrical length selected such that the sum of the second electrical length plus the electrical length of the second pair of feedthroughs through the thickness of the sheet provides a half wave phase shift between the second pair of feedthroughs at the top surface of the sheet, thereby defining the second balanced output signal; a balanced electrical connector that connects the first and second pair of opposed feedthroughs to the top ends of the corresponding helical conductors.
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Specification