Tunable microstrip patch antennas
First Claim
Patent Images
1. An antenna including:
- a ground plane that is electrically conductive having a first side surface;
a first patch that is electrically conductive having;
at least one edge; and
a first side surface;
a dielectric layer positioned between said first patch and said ground plane, said dielectric layer including;
a first side surface in contact with said first side surface of said first patch; and
a second side surface in contact with said first side surface of said ground plane;
at least one tuning strip that is electrically conductive spaced from said at least one edge of said first patch and spaced from said ground plane by said dielectric layer;
an RF lead connected to said first patch;
switch means to electrically connect and disconnect RF energy, in correspondence with an applied DC bias, between said at least one tuning strip and said first patch;
a center hole through said patch, said dielectric layer and said ground plane; and
lines for supplying said applied DC bias to said switch means that pass through said center hole.
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Abstract
A patch antenna is provided with one or more tuning strips spaced therefrom and RF switches to connect or block RF therebetween. When RF is connected between the tuning strips and the patch, the tuning strips increase the effective length of the patch and lower the antenna'"'"'s resonant frequency, thereby allowing the antenna to be frequency tuned electrically over a relatively broadband of frequencies. If the tuning strips are connected to the patch in other than a symmetrical pattern, the antenna pattern of the antenna can be changed.
208 Citations
30 Claims
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1. An antenna including:
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a ground plane that is electrically conductive having a first side surface; a first patch that is electrically conductive having; at least one edge; and a first side surface; a dielectric layer positioned between said first patch and said ground plane, said dielectric layer including; a first side surface in contact with said first side surface of said first patch; and a second side surface in contact with said first side surface of said ground plane; at least one tuning strip that is electrically conductive spaced from said at least one edge of said first patch and spaced from said ground plane by said dielectric layer; an RF lead connected to said first patch; switch means to electrically connect and disconnect RF energy, in correspondence with an applied DC bias, between said at least one tuning strip and said first patch; a center hole through said patch, said dielectric layer and said ground plane; and lines for supplying said applied DC bias to said switch means that pass through said center hole. - View Dependent Claims (2, 3, 4)
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5. An antenna including:
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a ground plane that is electrically conductive having a first side surface; a first patch that is electrically conductive having; at least one edge; and a first side surface; a dielectric layer positioned between said first patch and said ground plane, said dielectric layer including; a first side surface in contact with said first side surface of said first patch; and a second side surface in contact with said first side surface of said ground plane; at least one tuning strip that is electrically conductive spaced from said at least one edge of said first patch and spaced from said ground plane by said dielectric layer; an RF lead connected to said first patch; and switch means to electrically connect and disconnect RF energy, in correspondence with an applied DC bias, between said at least one tuning strip and said first patch, said switch means including; a first diode having; a first polarity end; and a second polarity end, said first diode being connected with said first polarity end connected to said first patch and said second polarity end connected to said tuning strip; an RF transmissive capacitor connected to said first patch; a second diode having; a first polarity end; and a second polarity end, said second diode being connected in series between said RF transmissive capacitor and said tuning strip with said first polarity end connected to said tuning strip and said second polarity end connected to said RF transmissive capacitor; and a DC supply connected between said RF transmissive capacitor and said second diode to forward bias said diodes into conductive states so that RF energy can pass therethrough and to reverse bias said diode into high impedance states so that RF energy is blocked thereby. - View Dependent Claims (6)
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7. An antenna including:
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a ground plane that is electrically conductive having a first side surface; a first patch that is electrically conductive, said first patch being rectilinear having; four linear edges; and a first side surface; a dielectric layer positioned between said first patch and said ground plane, said dielectric layer including; a first side surface in contact with said first side surface of said first patch; and a second side surface in contact with said first side surface of said ground plane; pluralities of spaced tuning strips that are electrically conductive and are positioned respectively parallel to each of said linear edges on said first side surface of said dielectric layer; an RF lead connected to said first patch; and switch means to controllably electrically connect and disconnect RF energy between said tuning strips and said rectilinear patch, whereby a resonant frequency, a feed impedance, and an antenna pattern of said antenna can be changed. - View Dependent Claims (8, 9)
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10. An antenna including:
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a ground plane that is electrically conductive having a first side surface; a first patch that is electrically conductive, said first patch being shaped as a plane section of a right circular cone and having; at least one edge, said at least one edge being a closed curve; and a first side surface; a dielectric layer positioned between said first patch and said ground plane, said dielectric layer including; a first side surface in contact with said first side surface of said first patch; and a second side surface in contact with said first side surface of said ground plane; a plurality of spaced ring shaped tuning strips that are electrically conductive and that are positioned concentric to each other and said at least one edge of said first patch on said first side surface of said dielectric layer; an RF lead connected to said first patch; and switch means to controllably electrically connect and disconnect RF energy between said tuning strips and said first patch, whereby a resonant frequency of said antenna can be changed. - View Dependent Claims (11)
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12. An antenna including:
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a ground plane that is electrically conductive; a first patch that is electrically conductive having; at least one edge; means to electrically insulate and space said ground plane from said first patch; a plurality of tuning strips that are electrically conductive spaced from said at least one edge of said first patch and said ground plane; an RF lead connected to said first patch; and a plurality of switches to individually electrically connect and disconnect RF energy between respective ones of said tuning strips and said first patch. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. An antenna including:
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a ground plane that is electrically conductive; a first patch that is electrically conductive, said first patch being rectilinear and having; four linear edges; means to electrically insulate and space said ground plane from said first patch; pluralities of spaced tuning strips that are electrically conductive, each tuning strip being parallel to a respective one of said linear edges and said ground plane; an RF lead connected to said first patch; and a plurality of switches to individually electrically connect and disconnect RF energy between various ones of said pluralities of spaced tuning strips and said first patch, whereby a resonant frequency of said antenna and an antenna pattern thereof can be changed. - View Dependent Claims (22, 23)
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24. An antenna including:
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a ground plane that is electrically conductive; a first patch that is electrically conductive, said first patch being shaped as a plane section of a right circular cone; means to electrically insulate and space said ground plane from said first patch; a plurality of spaced ring shaped tuning strips that are electrically conductive and that are positioned concentric to each other and said first patch; an RF lead connected to said first patch; a plurality of switches to controllably electrically connect and disconnect RF energy between said tuning strips and said first patch, whereby a resonant frequency of said antenna can be changed. - View Dependent Claims (25)
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26. In an antenna that includes a ground plane that is electrically conductive, a patch of a fixed size that is electrically conductive having at least one edge, means to electrically insulate and space the ground plane from the patch, a plurality of conductive tuning strips spaced from the at least one edge of the patch and the ground plane, an RF lead connected to the patch, and a plurality of switches to individually electrically connect and disconnect RF energy between respective ones of the tuning strips and the patch, the patch supporting a resonance at a first RF frequency, a method of operation including the steps of:
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placing RF energy on the RF lead at a second RF frequency below the first RF frequency;
afterconnecting RF energy to at least one of the tuning strips positioned and dimensioned with respect to the patch so that the patch and the connected at least one tuning strip together have a resonant frequency that is about the second RF frequency. - View Dependent Claims (27, 28, 29)
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30. An antenna including:
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a ground plane that is electrically conductive having a first side surface; a first patch that is electrically conductive having; at least one edge; and a first side surface; a dielectric layer positioned between said first patch and said ground plane, said dielectric layer including; a first side surface in contact with said first side surface of said first patch; and a second side surface in contact with said first side surface of said ground plane; at least one tuning strip that is electrically conductive spaced from said at least one edge of said first patch and spaced from said ground plane by said dielectric layer; an RF lead connected to said first patch; and switch means to electrically connect and disconnect RF energy, in correspondence with an applied DC bias, between said at least one tuning strip and said first patch, said switch means including; a first diode having; a first polarity end; and a second polarity end, said first diode being connected with said first polarity end connected to said first patch and said second polarity end connected to said tuning strip;
a second diode having;a first polarity end; and a second polarity end, said second diode being connected with said first polarity end connected to said patch and said second polarity end connected to said tuning strip; an RF transmissive capacitor connected to said first patch; an inductor connected between said RF transmissive capacitor and said second polarity end of said second diode, said inductor having an inductance such that, when combined with parasitic capacitances of said first and second diodes, said RF transmissive capacitor and said inductor form a parallel resonant circuit; and a DC supply connected between said RF transmissive capacitor and said inductor.
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Specification