JPH03286603A - Microstrip antenna - Google Patents

Abstract

PURPOSE: To obtain a radiator array which is low-cost, lightweight, and durable and can be mass-produced. CONSTITUTION: A radiator 14, a feed line 15, and dielectric layers 16 and 17 are arranged on a right plane and a radiator 14 and dielectric layers 16 and 17 are arranged in parallel to a ground reference surface 13. The dielectric layer 16 below the radiator 14 is less in dielectric constant than usual and the dielectric layer 17 belong the feed line 15 is different in dielectric constant from the radiator 14, thereby providing proper bandwidth, proper beam width, and proper gain for the radiator 14 and also providing minimum conduction and dielectric loss for the feed line 15.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a new and improved microstrip antenna and an array of radiators in the microstrip antenna.

(Prior Art and Problems to be Solved by the Invention) Microstoso-knob antennas for radio wave propagation that have been provided so far generally include a ground reference plane and one or more thin, flat dielectric radiators, Connected to the radiator is a thin, flat, electrically conductive feedline. The radiator and feedline have hitherto been attached to a common relatively costly dielectric layer. The dielectric material used was Teflon fiberglass, a solid material with a dielectric constant of about 2.3 to 2.6. This material is relatively expensive, on the order of $100 to several hundred dollars per square foot. The loss dissigent (loss coefficient) was approximately 0.0 at 10 gH2.
It is 001.

U.S. Patent No. 3,803,623, U.S. Patent No. 3,995,2
No. 77, No. 3, No. 987.455, No. 4,180,
No. 817 and Re 29,911 are examples of prior art regarding microstrip antennas. There is a need for low-cost, lightweight, durable, and readily mass-producible antennas with useful bandwidth for use in a variety of mass markets. The microstrip antenna disclosed herein has a radiator (
radiator> and ground reference plane (a 8 round reference
feed line (
feed line) and the ground reference plane, the latter providing improved performance and lower feed line losses at lower values. The dielectric layer between the radiator and the ground reference plane is a lower value and less costly material than traditionally used in microstrip antennas.

An array of four radiators provides both horizontal and vertical polarization of the radio energy.
yontal and vertical polar
iyation) isolated pol
aryation) and circular poles (circul
ar polarization). The radiators are sequentially cohort fed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, FIGS. 1 and 2 show a microstrip antenna 12 which is connected to a ground reference plane 13, a radiator 14 and at one end the bottom edge of said radiator 14. Feed line 15 connected to
including. A feed point 18 is located at the end of the feed line 15 opposite the connection to the radiator. A dielectric layer or base layer 16 is disposed between the radiator 14 and the ground reference plane 13, and a dielectric layer 17 is disposed between the feedline and the ground reference plane 13.

The edges of dielectric layer 16 extend a distance slightly beyond the edges of radiator 14 to contain the electric field around the radiator. Preferably, said distance is at least 2-3 times the thickness of dielectric layer 16.

In the embodiment shown in FIGS. 1 and 2, the ground reference plane is flat or a straight plane, and the radiators, feed lines, and dielectric layers are also straight flat or straight planes. The radiator 14 and the dielectric layer 16 , 17 are arranged parallel to the ground reference plane 13 . However, it is understood that the ground reference surface 13 may vary in shape from the straight flat surface shown, for example to a concave or convex surface or other curved surface.

The term "generally planar" refers to both straight and curved planar surfaces. The ground reference plane 13 may also be referred to as conforming to the support surface of the antenna, as it can conform to a variety of shaped surfaces to which the antenna is mounted.

“Polarization” (“polariyati”) as used herein
The term "on") indicates the plane of the electric field lines with respect to the horizontal plane of the ground. With respect to the diagram, the horizontal electric field lines extend across the diagram, i.e. laterally, indicating horizontal polarization, and the vertical Electric field lines extend up and down in the drawing to indicate vertical polarization. Linear polarization refers to either horizontal or vertical polarization. When combined, they exhibit coplanar or slanted linear polarizations, and can be combined to create left- or right-handed polarizations.Electric field lines extending in a clockwise circle indicate left-hand circular polarizations.

The illustrated radiator 14 is in the form of a thin conductive patch and each feed line is in the form of a thin conductive narrow strip. Although the illustrated patches are square to reduce bandwidth, it is understood that rectangular shapes of selected length and width dimensions may also be used. Preferably, the patch and feedline are fabricated as a single integral strip using photolithographic techniques. The preferred material for the pipe and feed line is copper soaked in a tin dip to prevent corrosion. The preferred thickness is approximately 0.038 mm (
0,0015 inches). The ground reference plane 13 is provided by the upper surface of a flat conductive rigid sheet of uniform thickness of conductive material such as aluminum rim, steel, etc., and provides support for other antenna elements placed and fixed on this rigid sheet. provide. 3.18 mm (0,125 inch) thick aluminum and 159 mm (0,06 inch) thick aluminum
25 inches thick steel is suitable for this component.

The dielectric layer 16 below the radiator is preferably a polyolefin, particularly a thin film of polyethylene on which the radiator is formed and of which it is an integral part. The dielectric constant of the dielectric layer under the radiator is lower than in the prior art, preferably about 101 to 1.50. The dielectric constant of the dielectric layer below the feed line 15 is the same as that of the radiator 14.
In the illustrated embodiment, air has a dielectric constant of 1.0. The above arrangement of dielectric layers provides adequate bandwidth, adequate beamwidth and adequate gain for the radiator, and minimal conductive and dielectric losses for the feed line.

One method of providing the radiator 14 shown in FIG. 3 is to adhere a conductive sheet of uniform thickness to a carrier layer 19 of film, preferably Mylar, which supports the conductive sheet except in the radiator and feed line portions. It is to remove it from the layer. This can be done using well-known photolithographic techniques.

An example of a material that has been found to be particularly suitable for use as dielectric layer 16 according to the present invention is as follows.

Polyethylene Closed Cell Semi-rigid Density 1.8-2.2 Thermal Conductivity B T U /parallel feet/hour/°F/inch 0.
35 (at an average temperature of 70 degrees) Tensile strength psi 20-30 Maximum service temperature 160 degrees F Burn rate 2.5 inches/minute Dielectric constant 1.05 (at 109 hZ)
Loss tangent (loss factor) 0.0002 (at 109 hZ) This type of material is available at a relatively low cost on the order of a few cents per square foot.

Examples of materials that have been found suitable for use as support layer 20 are as follows.

Mylar permittivity (at 106hZ) 2.3-2.6 Loss factor (at 10'hZ) 0.01-0.03 Water absorption % l/16 inch 0.2-0.4 Thickness 0.001- 0.005 inches. Referring now to FIG. 4, another form of microstrip antenna is shown in which a layer of superstrate 20 is placed over the radiator 14 and has the same overall dimensions as the radiator 14. This provides significantly greater gain to the antenna by a factor of 5. A suitable material for this purpose is alumina, which has a dielectric constant of about 10.

Reference materials with dielectric constants in the range from 6 to 12 are suitable for this purpose.

The microstrip antenna with multiple radiator arrays shown in FIG. 5 is arranged in the upper left corner of the drawing as upper left, upper right, lower left and lower right; It has an array A of four identical spaced apart radiators 14, each referred to as a radiator. The radiators in array A may be described as spaced apart in a common plane. Each radiator 14 has a length of approximately half a wavelength (γ/2), and the radiator has a length of approximately half a wavelength (γ/2), measured from one edge to the adjacent edge.
7/2).

A first feed line 21 is connected between the top and bottom edges along the vertical centerline of the upper left and lower left radiators, and a second feed line 22 is connected along the vertical centerline of the upper left and lower right radiators. They are connected along the centerline between the top and bottom edges to form two series radiator arrays that are juxtaposed. The third feed line 23 is connected at the bottom end to two series arrays with sections aligned with the first and second feed lines, the radiator and the feed line being connected to the linear, specifically vertical polarization of the radio wave energy. I will provide a. It is also understood that the feed line 23 could be connected to the top end of the top radiator with similar results.

The feed line 24 runs from the transformer segment 25 at the intermediate combination point between the ends of the feed line 23 to the adjacent four on the right side of the first mentioned array A.
radiators are connected to the corresponding transformer segments of array A. The feed line 26 is connected from the transformer segment 27 at the intermediate combination point between the ends of the feed line 24 to the corresponding transformer segments 27 of the two lower adjacent four radiators A.

The transformer segment 25,27 and the transformer following it are for impedance matching.

The feed line 28 connects the transformer segment 2 at an intermediate combination point between the ends of the feed line 26.
9 to two corresponding transformer segments of the four arrays of four adjacent four radiators on the right side of the four arrays of four radiators described above.

The feed line 31 connects the transformer segment 3 at the intermediate combination point between the ends of the feed line 28.
2 to the corresponding transformer segments 32 of the eight arrays of four radiators below the eight arrays of four radiators described above. The feed lines for the 64 radiators shown in FIG. 5 are midway between the ends of feed lines 31.

Referring now to FIG. 6, an alternative version of the microstrip antenna having an array of four radiators 14 as shown in FIG. The feed line 23 connected to the bottom end of the series array has an air gap between the feed line 23 and the ground reference surface 13 similar to that shown in FIG. The feed point 40 for this array is transformer segment 2
at the end of the feed line 24 opposite the connection with one feed line via 5.

By using the basic equations for the impedance of an equal circuit for a microstrip radiator, the bandwidth, beamwidth and gain parameters can be determined using the dielectric constant (
It can be readily demonstrated that it varies proportionally with Er). Furthermore, by using the basic equations for the impedance of an equal circuit for a microstrip feedline, it can also be readily demonstrated that conductive and dielectric losses vary directly in relation to the dielectric constant of the dielectric layer.

Referring now to FIG. 7, a microstrip antenna having an array of four radiators similar to those shown in FIGS. 3 and 6 is shown. A vertical polarizing feed point 37 is located at the intermediate combination point between the ends of the feed line 23. Additionally, a fourth feed line 34 is connected between the upper left and upper right radiator sides, and a fifth feed line 35 is connected between the lower left and lower right radiator sides. forming a set of two direct arrays. A sixth feed line 36 is connected between the left sides of the two series arrays in the upper left and lower left radiators. Feed line 36 has a portion aligned with the fourth and fifth feed lines and has a horizontal polarized feed point 3.
8 is located midway between the ends of the feed line 36 so that the radiator polarizes the radio wave energy in the horizontal direction. It is also understood that the feed line 36 can be connected to the right side of the upper right and lower right radiators with similar results.

This arrangement polarizes the energy radiated at feed point 37 vertically and horizontally at feed point 38.

Referring now to FIG. 8, a microstrip antenna is shown having an array of four radiators connected similarly to the array shown in FIG. In this arrangement, the transformer segment 48 at the intermediate combination point of the feed line 23 includes a seventh feed line 47 connected to up to four transformer segments at the intermediate combination point between the ends of the feed line 23.
The radio energy at feed point 51 intermediate between the combination points of One feed point 52 provides the right circular pole and feed line 23
A feed point 53 at a quarter-wave distance from the point of union of feed lines 47 toward provides the left circular pole.

Referring now to FIG. 9, a microstrip antenna having an array of four radiators is shown, where the first feed line 55 is connected to the lower left corner of the upper left radiator and to the upper left corner of the lower left radiator. A second feed line 56 is connected between the lower left corner of the third radiator and the upper right corner of the fourth radiator. Additionally, a third feed line 57 is provided connected between the lower left corner of the lower left radiator and the lower left corner of the lower right radiator. A transformer segment 58 is connected at an intermediate mating point between the ends of feed line 57. Each radiator shown in FIG. 9 has an aperture 59 that is the same square as the radiator but about 1/4 the width, and a feed line 60 connected to the segment 58 has a feed point 61 for this antenna. This arrangement provides a circular pole of electrolytic energy.

Referring to FIG. 10, there is shown a microstrip antenna including four arrays B of four radiators each connected in the same manner as in FIG. 7 described above.

The feed line 62 is connected between the vertical polarization combination points intermediate between the ends of the feed lines 23 of the upper left array and the lower left array. Similarly, a connection is made between the intermediate vertical polarization combination points between the ends of the feed line 23. Transformer segment 61 is connected to the end of feed line 62. A 180 degree phase shifter 63 is connected to the feed line 62 to generate radio wave energy phasewise at a combination point intermediate between the ends of the feed line 62. The feed lines 65 for the two left-hand arrays are connected at one end to the transformer segment 64 at the intermediate combination point between the ends of the feed lines 62 and at the other end to the top side of the power patch 66, while the Another feed line 65 from the right array is connected to the bottom side of power patch 66 and provides vertical polarization thereto.

Feed line 72 has a horizontal polarization combination point intermediate between the ends of feed line 36 for the two upper arrays and a horizontal polarization point intermediate between the ends of feed line 36 for the two lower arrays. connected between the combination points. A transformer segment 71 is connected to each end of feed line 72. A 180 degree phase shifter 75 is connected to feed line 72 and phase shifter 75 is connected to feed line 72 .
Radio wave energy is generated at a combination point intermediate between the two ends. Feed line 74 is connected at one end to transformer segment 73 at a mid-mating point between the ends of feed line 72 and at the other end to the right of patch 66 for the two upper arrays and to the right of patch 66 for the lower array. It is connected to the left side of 66. patch 6
A dielectric layer 67 is provided between 6 and the ground reference plane.

Horizontal polarizing feed points 78 are provided on feed lines 74 associated with the two lower arrays. Horizontal polarizing feet 78 are located at an integral number of wavelengths from the combination point on feed line 72. The feed lines 65 associated with the two right-hand arrays are provided with vertical polarizing feed points 79. The vertical polarizing feed points 79 are located at an integral number of wavelengths from the combination point of the feed lines 62. positioned.

This arrangement allows for vertical power [!] from the upper and lower left arrays at the top of the power patch 66. The radio energy and the vertically polarized radio energy from the upper and lower right arrays are simultaneously applied across the zero axis to the bottom of the power patch and block each other. At the same time, horizontally polarized radio energy is applied from the upper array to the right side of the power patch, and is applied from the lower array to the left side of the power patch across the zero axis, thereby blocking each other. In this way, an antenna is provided in which linear polarization of radio wave energy is blocked.

Referring now to FIG. 11, there is shown an array of four radiators, each radiator 14 disposed on a dielectric layer 16 on a ground reference plane 13. A first feed line 81 is connected between the upper left radiator and the upper right radiator, and a second feed line 82 is connected between the lower left radiator and the lower right radiator.

A feed line 86 having transformer segments 85 at its ends is connected to a mid-mating point between the ends of the first feed line 81 and a mid-mating point between the ends of the feed line 82 . These feed lines 81 and 82 have mutually aligned portions along a straight line of radio wave energy, in particular a line perpendicular to vertical polarization.

The feed point 87 of this antenna is midway between the ends of the feed line 86. This arrangement can be characterized as a cohort feed array and provides linear polarization. In the illustrated position, the radiator provides vertical polarization and if rotated 90 degrees provides horizontal polarization.

The antennas shown in Figures 5 through 11 are all phased arrays, with a plurality of radiators configured to emit or receive radio wave energy perpendicular to the plane of the antenna. It means that.

It will be appreciated that with a phased array, the radio energy from the feed points will arrive at the subarrays at the same time, but the arrays may be configured to arrive at the subarrays at different times to provide stearate beams.

Although the invention has been described in some detail, it is understood that this description has been done by way of example and that details of construction may be changed without departing from the spirit of the invention.

[Brief explanation of the drawing]

FIG. 1 is a top plan view of a microstrip antenna embodying the features of the present invention suitable for linearly polarizing radio wave energy; FIG. 1; FIG. 3 is a cross-sectional view of another form of microstrip antenna modified from that shown in FIG. 2 showing the carrier layer supporting the radiator; FIG. 4; 5 is a cross-sectional view of another form of a microstrip antenna modified from that shown in FIG. 2, using a superstrate layer on top of the radiator; FIG. A top plan view of a microstrip antenna; FIG. 6 shows an alternative configuration of a microstrip antenna with multiple radiator arrays using a single dielectric sheet supporting an array of four radiators; FIG. 8 is a top plan view of another form of a microstrip antenna arranged to provide both horizontal and vertical polarization; FIG. FIG. 9 is a top plan view of another form of a microstrip antenna arranged to provide a circular pole, FIG. FIG. 11 is a top plan view of another embodiment of a microstrip antenna with multiple radiator arrays, and FIG. FIG. In the figure, 12...Microstrip antenna 13...Ground reference plane 14...Radiator (radiator) 15...
Feed line (power supply line) 16.17... Dielectric layer 19.20... Support layer 21.22, 23.24.
...Feed line 26.283132...Feed line 30...Dielectric layer 34.3536...Feed line 37, 38.40...Feed point (power feeding point) 47.48...Feed line 3
1521, feed point 55, 56, 57.60
...Feed line 61...Feed point
62...Feed line 63...Phase shifter 6
5...Feed line 66...Power patch 7
2.74...Feed line 75...Phase shifter 78...Feed point 818286...Feed line 87...Feed point agent

Claims (1)

Claims: 1) a ground reference plane, a radiator in the form of a microstrip patch, a microstrip feed line connected to an edge of the radiator, disposed between the radiator and the ground reference plane; a first dielectric layer having a first selected dielectric constant; and a second dielectric layer disposed between the feedline and the ground reference plane and having a second selected dielectric constant; the first dielectric constant is different from the second dielectric constant, the first dielectric constant being selected to provide a selected bandwidth, a selected beamwidth and a selected gain for the radiator; A microstrip antenna characterized in that the second dielectric constant is selected to provide a selected low conductive loss and a selected low dielectric loss for the feedline. 2) In the antenna according to claim 1,
The microstrip antenna wherein the first dielectric constant is about 1.01 to 1.5 and the second dielectric constant is about 1.0. 3) In the antenna according to claim 1,
A microstrip antenna that confines an electric field around the radiator by extending an edge of the first dielectric layer around the radiator and a selected small distance beyond the edge of the radiator. 4) In the antenna according to claim 3,
A microstrip antenna, wherein the first dielectric layer extends a distance of at least two to three times the thickness of the first dielectric layer. 5) In the antenna according to claim 1,
A microstrip antenna, wherein the first dielectric layer is a polyolefin. 6) In the antenna according to claim 5,
A microstrip antenna, wherein the polyolefin is polyethylene. 7) In the antenna according to claim 1,
A microstrip antenna comprising a layer of superstrate having a dielectric constant in the range of about 6 to 12 on the radiator to increase gain. 8) In the antenna according to claim 1,
A microstrip antenna, wherein the second dielectric layer is provided by providing an air gap between the ground reference plane and the feed line. 9) In the antenna according to claim 1,
A microstrip antenna in which the radiator and feedline are formed as a single integral strip of the same conductive material. 10) A microstrip antenna according to claim 1, wherein a carrier layer of uniform thickness throughout supports the radiator and feedline. 11) A microstrip antenna according to claim 10, wherein the carrier layer is mylar. 12) A microstrip antenna according to claim 1, wherein the radiator has a generally rectangular shape to regulate bandwidth. 13) a ground reference surface; and first, second, third and fourth radiators spaced apart from each other and each in the form of a microstrip patch, the second radiator as viewed from above the radiator; is located below the first radiator, and the third radiator is located to the right of the first radiator,
a radiator in which the fourth radiator is located below the third radiator and to the right of the second radiator; and a bottom edge and a top edge of each of the first and second radiators. a first microstrip feed line connected between a first microstrip feed line and a second microstrip feed line connected between a bottom edge and a top edge of each of said third and fourth radiators; a feed line forming two series radiator arrays; and a feed line connected to the ends of said two series arrays and connected to said first
a third microstrip feedline having a portion aligned with the second feedline and a combination point for vertical polarization of radio energy intermediate between the ends of the radiator and the ground reference plane; a first dielectric layer having a selected first dielectric constant disposed therebetween; and a first dielectric layer having a selected second dielectric constant disposed between each of the feed lines and the ground reference plane. 2 dielectric layers, the second dielectric constant being such that the first dielectric constant provides a selected bandwidth, a selected beamwidth and a selected gain for the radiator. A microstrip antenna, wherein the second dielectric constant is selected to provide a selected low conductive loss and a selected low dielectric loss for the feedline. 14) The antenna according to claim 13, wherein the first dielectric layer has the following characteristics for all radiators:
A microstrip antenna that is a single sheet with an outer edge extending a selected small distance beyond the two outer edges of the radiator. 15) An antenna according to claim 13, wherein for each radiator the outer edge extends a selected small distance beyond the edge of the associated radiator. Microstrip antennas that are individual sheets. 16) The antenna according to claim 13, wherein four of the first, second, third and fourth radiators
groups, the groups being on the upper left, the lower left, the upper right and the lower right, viewed from above, with a fourth microstrip feed line between the vertical polarization combination points of the radiators of the upper group and the A fifth microstrip feed line is connected between the vertically polarized combination points of the radiators of the lower group, a fifth microstrip feed line is connected between the combination points intermediate between the ends of said fourth feed line, and a sixth microstrip feed line is connected between the combination points midway between the ends of said fourth feed line. A strip feed line is connected between the end of said fifth feed line and an intermediate combination point between similar fifth feed lines of a similar group of 16 radiators; is a microstrip antenna connected between the intermediate combination point between the ends of said sixth feed line and the intermediate feed point between its ends to a similar group of 32 radiators. 17) The antenna according to claim 13, comprising: a first feed point connected to the combination point; and a fourth microstrip feed line connected between the first and third radiators. a second set of two series arrays including a fifth microstrip feed line connected between the second and fourth radiators and at the ends of the second set of two series arrays; a sixth microstrip feedline having a portion connected and aligned with the fourth and fifth feedlines and an end of the sixth microstrip feedline for horizontal polarization of radio wave energy; and a second feed point of the microstrip antenna. 18) The antenna according to claim 17, further comprising a seventh microstrip feed line connected between the combination points of the first and second sets of arrays; A microstrip antenna that includes a sloped straight polarized feed point halfway between the ends of the strip feed line. 19) An antenna according to claim 18, comprising a right circular pole feed point in the seventh feed line and a left circular pole feed point in the seventh feed line. . 20) The microstrip antenna of claim 13, wherein the radiator has dimensions of about half a wavelength and is spaced about half a wavelength from edge to adjacent edge thereof. 21) An antenna according to claim 13, wherein each radiator has a central aperture that is generally the same in shape as the radiator but whose dimensions are approximately one-fourth of the dimensions of said radiator; feed lines are connected to the first and third feed lines.
the second feed line is connected from diagonally adjacent corners of the third and fourth radiators, and the third feed line is connected from the diagonally adjacent corners of the third and fourth radiators; and a corner of the fourth radiator, the third feed line having a combination point intermediate between its ends and a feed point connected to the combination point; Microstrip antenna with circular energy poles. 22) The antenna according to claim 13, wherein four of the first, second, third and fourth radiators
groups, the groups are arranged as upper left, lower left, upper right and lower right groups when viewed from above, and a fourth microstrip feed line is arranged at the bottom of the upper left group and the lower left group. a vertical polarization combination point between the top of the upper right group and the vertical polarization combination point of the upper right group and the lower right group by arranging a 180 degree phase shifter in each fourth feed line; the radio wave energy at a first combination point intermediate between the ends of the four feed lines is phase matched at said first combination point, and a fifth microstrip feed line is located on the opposite side of said upper group; a 180 degree phase shifter connected between a horizontal polarization combination point on the opposite side of the lower group and a horizontal polarization combination point on the opposite side of the lower group; 6 microstrip feed lines connected to the top of the power patch and from the right group to the bottom of the power patch to provide interrupted vertical polarization, and a combined horizontal polarization from said upper group to the bottom of the power patch; a feed line connected to the right side of the patch and from the lower group to the left side of the power patch to provide interrupted horizontal polarization; a vertical polarization feed point on the sixth microstrip feed line; and a horizontal polarization feed point on the seventh microstrip feed line. 23) a ground reference plane and a first radiator spaced apart from each other, each radiator being in the form of a microstrip conductive patch;
, an array of second, third and fourth radiators, the second radiator being located to the right of the first radiator when viewed from above, and the third radiator being located to the right of the first radiator. an array of radiators arranged below, the fourth radiator being below the first radiator and to the right of the third radiator; a first microstrip feed line connected between the bottom edges of the radiator; and a first merging point on the first feed line intermediate between the ends of the first feed line. , a second microstrip feed line connected between the bottom edges of the third and fourth radiators; a third microstrip feed line connected between said combination points, and an end of said third feed line for vertically polarizing radio wave energy; a first dielectric layer disposed between the radiator and the ground reference plane and having a first selected dielectric constant; and between each of the feed lines and the ground reference plane. a second dielectric layer disposed in the radiator and having a second selected dielectric constant, the first dielectric constant being different from the second dielectric constant, and the first dielectric constant being disposed in the radiator. the second dielectric constant is selected to provide a selected bandwidth, a selected beamwidth and a selected gain for the feed line, and the second dielectric constant is selected to provide a selected low conductive loss and low dielectric A microstrip antenna characterized in that it is selected to provide loss.