Multi-layer antenna with dual-band patches

Abstract

To provide a software-defined antenna that can control a delay line using a variable dielectric and control the directivity of an antenna.SOLUTION: An array antenna 100 is accompanied by a plurality of radiation patches 210, which operates in one direction in one frequency band and in a second direction orthogonal to the first direction in another frequency band. The signal from each of the radiation patches 210 is coupled to two delay lines 215 and 217. The delay lines 215 and 217 cross over a variable relative permittivity plate. Beam scanning can be performed by changing the relative permittivity of a VDC plate near the delay line to introduce signal delay by controlling the voltage potential of the delay line.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] [Related Applications] This application claims priority to U.S. Provisional Application No. 62 / 936,283, filed November 15, 2019, the disclosure of which is incorporated herein by reference in its entirety.

[0002] [Technical field] The disclosed invention relates to a radio transmitting antenna and a method for manufacturing such an antenna. [Background technology]

[0003] [Related Technology] In a previous disclosure, the inventors disclosed an antenna that utilizes a variable dielectric constant (VDC) to control antenna characteristics. Details of that antenna are disclosed in U.S. Patent No. 7,466,269, the entire disclosure of which is incorporated herein by reference. In the previous disclosure, the inventors detailed how an array antenna can be steered or scanned using software control to separately vary the dielectric constant of domains near each delay line. The present disclosure implements a similar steering / scanning mechanism, but allows software control to be implemented in antennas that transmit and receive in various frequency bands. Summary of the Invention

[0004] The following summary of the present disclosure is intended to provide a basic understanding of some aspects and features of the present invention. This summary is not an extensive overview of the invention, and as such is not intended to particularly identify key or critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented below.

[0005] The present disclosure provides various enhancements and advancements to variable dielectric constant antennas, including improved array antennas and methods of manufacturing such array antennas.

[0006] The embodiments of the present invention provide a software defined antenna that uses a variable dielectric to control the delay line, thereby creating a phase shift with respect to the spatial direction of the antenna. The embodiments disclosed herein decouple the antenna from the corporate feed design. The embodiments disclosed herein further decouple the RF and DC potentials from the orthogonal delay line. The various elements of the antenna, such as the radiators, corporate feed, variable dielectric, and phase shift control lines, are located on various layers of a multi-layer antenna design.

[0007] Disclosed features include configurations for coupling RF signals between radiating elements and feed lines, configurations for dual frequency bands for transmission and reception, configurations for increasing bandwidth, and methods for manufacturing the antenna.

[0008] Other aspects and features of the present invention will become apparent from the detailed description, which takes place in conjunction with the following drawings, which should be understood as providing various non-limiting examples of various embodiments of the invention, as defined by the appended claims.

[0009] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the detailed description, serve to explain and illustrate the principles of the invention. The drawings are intended to illustrate, in a schematic manner, major features of exemplary embodiments. The drawings are not intended to show every feature of an actual embodiment or the relative dimensions of the depicted elements, and are not drawn to scale. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a top view illustrating an array according to an embodiment of the disclosure. [Diagram 2] FIG. 2 is a top view illustrating one element of an array antenna according to one embodiment. [Figure 2A] FIG. 2A illustrates another embodiment of a dual band patch configuration. [Figure 3A] FIG. 3A is a top view of a multi-layer array antenna structure according to one embodiment. [Figure 3B] FIG. 3B is a cross-section of a multi-layer array antenna structure according to one embodiment. [Figure 4] FIG. 4 is a top "see-through" view illustrating the structure of the dual-band array antenna. [Diagram 5] FIG. 5 is a cross section of a multi-layer array antenna according to another embodiment. [Figure 6] FIG. 6 is a cross section of a multi-layer array antenna according to yet another embodiment. [Figure 7] FIG. 7 is a cross section of a multi-layer array antenna according to a further embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The embodiments of the antenna of the present invention will now be described with reference to the drawings. Various embodiments or combinations thereof can be used for various applications or to obtain various advantages. The various features disclosed herein can be used in part or in whole alone or in combination with other features, depending on the results to be obtained, balancing the advantages with requirements and constraints. Thus, certain advantages are highlighted with respect to various embodiments, but are not limited to the disclosed embodiments. That is, the features disclosed herein are not limited to the embodiments in which they are described, but can be "mixed and matched" with other features and incorporated into other embodiments.

[0012] 1 illustrates a top view of an embodiment of an antenna 100. Generally, the antenna is a multi-layer printed antenna including a patch layer, a true time delay layer, a ground layer, and a corporate feed layer, as described in more detail below. In some cases, additional layers are added to provide multiple polarizations, wide bandwidth, etc.

[0013] As shown in FIG. 1, the array antenna 100 in this particular example includes a 4×4 array of parasitic radiators 210, although any number of radiators can be used, and 4×4 is chosen only as an example. Each parasitic radiator 210, obscured from view in this view by the parasitic radiators 210, is located on top of the insulating layer 105 above a corresponding dual-band patch. The dual-band patch has two delayed feed lines 215 and 217 physically or capacitively coupled thereto, as described further below. Each delayed feed line 215, 217 feeds an RF signal to its corresponding dual-band patch, which couples radiated energy to the parasitic radiator 210. This RF signal can be manipulated, e.g., delayed, frequency shifted, phase shifted, by controlling the variable dielectric layer. By controlling all of the delay lines 215 and 217, the array can be variously oriented or scanned as desired, resulting in a scanned array. Incidentally, although the delay lines are shown in Figure 1, this is done for ease of understanding only, and are not visible in this top view, as they would normally be covered by dielectric 105.

[0014] FIG. 2 illustrates the configuration of a dual-band patch 220, which is obscured by the parasitic radiators 210 of FIG. 1 (one patch 220 under each parasitic radiator 210). The patch 220 is configured to transmit and receive in two separate bandwidths orthogonally. That is, one of the delay lines 215 and 217 is dedicated to transmit, while the other is for receive, and the transmit and receive signals travel orthogonally to each other through the patch. Thus, each delay line transmits signals at different frequencies selected from different bandwidths. This is done by coupling the delay lines to a bias-t. However, for effective use of the bias-t, the design of the patch is such that there is no galvanic connection between the two delay lines in the patch. This is done as follows:

[0015] One delay line, e.g. receive at low frequencies, is connected to the patch by ohmic contact, while the other delay line, e.g. transmit at higher frequencies, is coupled to the patch by capacitive coupling without ohmic connection. This is illustrated in Fig. 2 as follows: The transmit delay line is connected to the patch 220 from below at contact point 223. When the delay line is formed on the lower layer, it is connected to the contact point 223 using a via, as shown in Fig. 3. Conversely, the other delay line is connected to contact point 227, which is provided on the coupling patch 225. The coupling patch 225 forms a capacitor with the patch 220 across the gap d1, thus allowing transmission of RF signals between the patches 220 and 225, but preventing the passage of DC currents therebetween.

[0016] 2 is an optional feature attached to the radiating patch to broaden the bandwidth. The LC circuit is formed by adding a nearby patch 229, which may also be called a capacitive patch, with a gap d2 between them, which sets up the capacitive part of the LC circuit, and the patch itself forms the inductive part of the LC circuit at the selected frequency.

[0017] The structure and operation of the antenna shown in Figures 1 and 2 can be better understood from the following description of Figures 3A and 3B, and with further reference to Figure 4. Figure 3A illustrates a top view of a single patch 220, and Figure 3B illustrates a cross-section of the relevant portion of the antenna at the location of patch 220 in Figure 3A. Figure 4 provides a top "see-through" view that may be applied to the embodiments described herein, including those of Figures 3A and 3B. Thus, when considering any of the embodiments disclosed herein, reference should also be made to Figure 4 for a better understanding.

[0018] The parasitic radiator 210 is formed on a dielectric spacer 310, which may be glass, PET (polyethylene terephthalate), etc. At each patch location of the parasitic radiator 210, a radiating patch 220 is formed below and aligned with the parasitic radiator 210. The parasitic radiator 210 may have a larger lateral dimension than the radiating patch 220 to increase the bandwidth, but may have approximately the same shape as the radiating patch 220. RF energy is coupled between the parasitic radiator 210 and the radiating patch 220. Thus, when the radiating patch 220 radiates RF energy, the RF energy is coupled into the parasitic patch 210, which then radiates from the parasitic radiator 210 to the surroundings. Conversely, when the parasitic radiator 210 receives an RF signal, it couples the signal into the radiating patch 220, which is then sent to the transceiver (not shown) by the coupling patch 225 and the delay line 217.

[0019] 3B, a via 125 is formed and filled with a conductive material, e.g., copper, to form a contact 325 that is physically and electrically connected, i.e., forming an ohmic contact, to the radiating patch 220. A delay line, e.g., 215, is formed on the bottom surface of the dielectric spacer and is physically and electrically connected to the contact 325. That is, there is a continuous DC electrical connection from the delay line 215 to the radiating patch 220. As shown in FIG. 3A, the delay line is a meandering conductive line and can be of any shape with a length sufficient to create the desired delay, which can produce the desired phase shift in the signal.

[0020] The delay in the delay lines 215, 217 is controlled by a variable dielectric constant (VDC) plate 340, which in this example consists of a top binder 342 (e.g., glass, PET, etc.), a variable dielectric constant material 344 (e.g., a twisted nematic liquid crystal layer), and a bottom binder 346. The dielectric constant of the VDC plate 340 can be controlled by applying a DC potential across the VDC plate 340. To apply the DC potential, in this example electrodes 341 and 343 are formed and connected to a controllable voltage potential 351, for example a pulse width modulated DC supply. There are various configurations for forming the electrodes and although one example is shown, any conventional configuration for applying a DC potential to the VDC can be used.

[0021] As an example, electrode 341 is shown connected to variable potential 351 while electrode 343 is connected to ground. Alternatively, electrode 343 may be connected to variable potential 349 as shown by the dashed lines. Thus, by varying the output voltage of variable potential 351 and / or variable potential 349, the dielectric constant of the VDC material near electrodes 341 and 343 can be changed, thereby varying the RF signal traveling across delay line 215.

[0022] In this regard, it should be made clear that the use of the term ground in this description refers to a generally acceptable ground potential, i.e., earth potential, and also to a common or reference potential, which may be a set potential or a floating potential. Similarly, in the drawings, the symbol for ground is used, but this is used as a shorthand to mean either ground or common potential interchangeably. Thus, whenever the term ground is used in this specification, the term common potential or reference potential, which may be a positive or negative set or floating potential, is included in this specification.

[0023] The second delay line 217 is physically and electrically connected to the coupling patch 225 by vias 128. Another set of electrodes is used to apply a voltage potential to the LC near the delay line 217, but is not shown in the drawing as it is physically beyond the cross-section shown in Figure 3B. The inductive / capacitive LC patch 229 has no physical or ohmic connection to anything, it is electrically floating and forms an LC circuit with the radiating patch 220.

[0024] As with all RF antennas, transmitting and receiving are symmetrical, so a description of one applies equally to the other. In this description, it may be easier to explain transmitting, but receiving is the same, just in the opposite direction.

[0025] In transmit mode, the RF signal travels from the transceiver to the feed line 860, from there it is capacitively coupled to the delay line 215, from there through the via 125 to the radiating patch 220, the parasitic radiator 210, and then into air. In receive, the signal received by the parasitic radiator 210 is coupled to the radiating patch 220, from there to the coupling patch 225, thence to the delay line 217, and thence through the feed line 862 to the transceiver. In the illustrated example, some of the signal coupling is by ohmic contacts, while others are by capacitive coupling as follows:

[0026] As shown in the example of FIG. 3B, there is no electrical DC (ohmic) connection between the feed line 860 / 862 and the respective delay line 215 / 217. Rather, in this example, an RF short is provided such that the RF signal is capacitively coupled across a window formed in the ground plane. As shown in FIG. 3B, a window 353 is provided in the backplane ground (or common) 350 and aligned below a first end of the delay line 215 (the other end is connected to the contact 325). The RF signal travels from the feed line 860 through the window 353 and is capacitively coupled to the delay line 215. Similarly, a window 357 is provided in the ground plane 350 and aligned below a first end of the delay line 217 (the other end is connected to the via 128). During reception, the signal from the delay line 217 is capacitively coupled to the feed line 862 through the window 357.

[0027] To further understand the RF short (also referred to as virtual choke) design of the disclosed embodiment, refer to FIG. 4. For the transmit side of FIG. 4, the radiating patch 220 is electrically connected to the delay line 215 by a contact 825. As shown in FIG. 3B, the VDC plate 340 is located below the delay line 215, but is not shown in FIG. 4 for the sake of simplifying the drawing to facilitate understanding of the RF short feature. The backplane ground 350 is partially shown by hatching 850, which also shows a window 353. The length of the window 353, shown as "L", for effective coupling of the RF signal should be set to approximately half the wavelength traveling in the feed line 860, i.e., λ / 2. In that regard, whenever a wavelength λ is mentioned, it refers to the wavelength in the relevant medium, since the wavelength may change as it travels through various media of the antenna, depending on the design of the antenna and the DC potentials applied to the variable dielectric constant materials in the antenna. The width of the window, designated as "W", should be set to approximately one tenth of a wavelength, or λ / 10.

[0028] Moreover, for effective coupling of the RF signal, the feed line 860 extends approximately a quarter wavelength, or λ / 4, beyond the edge of the window 353, as shown by D. Similarly, the terminal end of the delay line 215 (the end opposite the contact 825) extends a quarter wavelength, or λ / 4, beyond the edge of the window 353, as shown by E. Note that the spacing D is shown to be longer than the spacing E because the RF signal traveling in the feed line 860 has a longer wavelength than the signal traveling in the delay line 215.

[0029] A similar capacitive coupling arrangement is provided to couple the receive signal from the delay line 217 to the feed line 860. Moreover, the signal from the radiating patch is capacitively coupled to the delay line 217 across the coupling patch 225. As shown more clearly in FIG. 3B, the coupling patch 225 is provided in the same plane as the radiating patch 220 and spaced d1 from the edge of the radiating patch 220. This arrangement allows RF signals to be transmitted between the radiating patch 220 and the coupling patch 225, but prevents DC signals from being transmitted between the radiating patch 220 and the coupling patch 225. This arrangement allows the receive signal to operate at a different frequency than the transmit signal without causing interference during the control of the VDC plate. Also, since the transmit and receive operations occur at different frequencies and are received at mutually orthogonal radiating patches, the radiating patches are not square, but rather more rectangular, and the radiating patches are different from each other in length and width.

[0030] Note that in FIG. 2, the patch is illustrated with two corners on one side chamfered, as shown at 228, thus forming what may be called a "pseudo-square". In this example, the chamfered corners are beneficial for at least two reasons. First, it prevents signal "leakage" between adjacent radiating patches. Sharp angles would result in high field concentrations that could lead to RF signal leakage. Moreover, one reason for the cutout being present on the side of the coupling patch 225 is to enhance the coupling of the RF signal between the radiating patch 220 and the coupling patch 225.

[0031] As noted, another feature of the present disclosure is the use of an inductive-capacitive LC circuit in the radiating patch to broaden the bandwidth. The LC circuit is formed by placing a capacitive or proximity patch 229 in the same plane as the radiating patch and the coupling patch 225, with a gap distance d2 from the side of the radiating patch 220, where the gap d2 (and the dielectric constant of the material in the gap) determines the capacitance of the capacitive part of the LC circuit, and the patch itself forms the inductive part of the LC circuit. Note that the capacitive patch 229 is electrically floating and isolated from any other conductive parts of the array antenna.

[0032] FIG. 2A illustrates another embodiment of a dual-band patch configuration with similar capacitive coupling of RF signals, similar to FIG. 2, but with a modified LC configuration. In particular, the length of the proximity patch 229 does not need to be the same as the radiating patch 220. In the embodiment of FIG. 2A, the length of the proximity patch 229 is shorter than that of the radiating patch 220. Moreover, the corners of the radiating patch 220 are rounded off on the side facing the proximity patch 229 and on the side facing the coupling patch 225. In this respect, the design of the radiating patch illustrated in FIG. 2 can be called a half pseudo-square, and although the design of FIG. 2A is called a pseudo-square, it is noted that the design is a rectangle that can also be called a pseudo-rectangle, which means a rectangular shape with rounded corners. Also, the parasitic patch 210 can be the same shape as the radiating patch 220 with rounded corners, except that the dimensions can be larger.

[0033] 5 illustrates an embodiment that benefits immensely from the features disclosed herein, in particular the separation of transmit and receive RF coupling to the radiating patch 220. In particular, in this embodiment, control voltages from DC power sources 351 and 349 are provided to the delay lines 215 and 217, respectively. Thus, when a DC potential is applied to the delay lines, the liquid crystal near the delay lines changes its dielectric constant in response to the applied potential. In operation, the potential applied to the delay line 215 is different from the potential applied to the delay line 217. Thus, by having one delay line with an ohmic contact to the radiating patch 220 and one delay line with a DC break to the radiating patch 220, DC isolation is created between the delay lines 215 and 217, while both delay lines still have RF coupling to the radiating patch 220.

[0034] From the above, it should be understood that the DC isolation feature is advantageous even if the radiating patch 220 is square, i.e., transmission and reception are performed in the same bandwidth. It should also be understood that the advantages of the disclosed invention can be implemented without the use of a parasitic radiator, as illustrated by the embodiment of FIG. 5, in which the signal from the radiating patch is radiated directly into the air, rather than into a parasitic patch. Of course, the same can be implemented in other embodiments disclosed herein. It should also be noted that in the embodiment of FIG. 5, the ground plane 350 serves as a ground for all of the antenna's RF and DC signals.

[0035] As shown, transmission and reception are symmetrical operations, and therefore, although the embodiment has been described with delay line 215 used for transmission and delay line 217 used for reception, it should be understood that the roles of the lines can be reversed, with delay line 215 being used for reception and delay line 217 being used for transmission.

[0036] Thus, an array antenna is provided, comprising an insulating substrate, a plurality of radiating patches provided on an upper surface of the insulating substrate, a plurality of first vias formed in the insulating substrate, each filled with a conductive material and each in electrical contact with one of the radiating patches, a plurality of capacitive patches provided on the upper surface of the insulating substrate, each spaced a distance d from one of the radiating patches, thereby forming a capacitor with one of the radiating patches, a plurality of second vias formed in the insulating substrate, each filled with a conductive material and each in electrical contact with one of the first vias, and a plurality of An array antenna is provided, comprising: first delay lines each connected to one of the first vias; a plurality of first control lines each connected to a voltage power supply and connected to one of the first delay lines; a plurality of second delay lines each connected to one of the second vias; a plurality of second control lines each connected to a voltage power supply and connected to one of the second delay lines; a variable dielectric constant (VDC) plate provided below an insulating substrate; and a ground plane provided on a surface of the VDC plate.

[0037] Figure 6 is a cross section of a multi-layer array antenna according to yet another embodiment. In the embodiment of Figure 6, feed lines 860 and 862 are directly connected to delay lines 215 and 217, respectively. It should be understood that the connections may be made in a plane perpendicular to the page, which is one reason why the feed lines are shown as dotted lines. Because the feed lines are directly connected to the delay lines, the ground plane 350 does not need to include a window for capacitive coupling of the RF signal.

[0038] Fig. 7 is a cross section of a multi-layer array antenna according to a further embodiment. In the embodiment of Fig. 7, the RF signal of delay line 217 is capacitively coupled to radiating patch 220 through coupling patch 225, while the RF signal of delay line 215 is capacitively coupled to radiating patch 220 through window 353 in ground plane 350. Thus, complete isolation is obtained between delay line 215 and delay line 217. Furthermore, control signals from voltage supply 349 affect the domain of VDC layer 340 near delay line 217, and control signals from voltage supply 351 affect the domain of VDC layer 341 near delay line 215. Ground plane 350 provides isolation between VDC layer 340 and VDC layer 341. Moreover, since each of delay line 215 and delay line 217 is on a separate layer, more "location" or space is available to make the serpentine delay line to the desired length and shape. Incidentally, the alignment of delay line 215 with respect to window 353 can be designed in a manner similar to that described with respect to FIG.

[0039] Thus, there is provided an array antenna comprising a dielectric substrate, a plurality of radiating patches disposed on the dielectric substrate, a plurality of coupling patches disposed on the dielectric substrate, each of which has a reduced spacing d with a corresponding one of the radiating patches, a ground plane sandwiched between a first variable dielectric constant (VDC) layer and a second VDC layer, each of which has a plurality of windows aligned under one of the plurality of radiating patches, a plurality of first delay lines, each of which is in ohmic contact with one of the coupling patches, and a plurality of second delay lines, each of which has a termination aligned with one of the plurality of windows and configured to capacitively couple RF energy to one of the radiating patches. The ohmic contacts may include a plurality of conductive vias formed in the dielectric substrate, each of which connects one of the first delay lines to a corresponding one of the coupling patches. The array antenna may further comprise a plurality of adjacent patches disposed on the dielectric substrate, each of which has a reduced spacing d2 with a corresponding one of the radiating patches. The array antenna may further include a plurality of first control lines, each connected to a voltage power supply and one of the plurality of first delay lines, and a plurality of second control lines, each connected to a voltage power supply and one of the plurality of second delay lines.

[0040] It should be understood that the processes and techniques described herein are not inherently related to any particular apparatus, but may be practiced by any suitable combination of components. Moreover, various types of general purpose devices may be used in accordance with the teachings described herein. While the invention has been described with reference to specific examples, these are intended in all respects to be illustrative rather than limiting. Those skilled in the art will recognize that a wide variety of combinations are suitable for practicing the invention.

[0041] Moreover, other implementations of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. Various aspects and / or components of the described embodiments may be used alone or in any combination. It is intended that the specification and embodiments be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

1. An antenna, An insulating substrate; a radiating patch disposed on a top surface of the insulating substrate; a first via formed in the insulating substrate and filled with a conductive material in contact with the radiating patch; a coupling patch disposed on a top surface of the insulating substrate and spaced a distance d1 from a first side of the radiating patch, thereby forming a capacitor with the radiating patch; a second via formed in the insulating substrate and filled with a conductive material in electrical contact with the bonding patch; a first delay line connected to the first via; a second delay line connected to the second via; A variable dielectric constant (VDC) plate; a ground plane disposed on a surface of the VDC plate; an inductive-capacitive circuit coupled to the radiating patch, the inductive-capacitive circuit including an electrically floating patch provided on an upper surface of the insulating substrate, the electrically floating patch being positioned on an opposite side of the coupling patch at a distance d 2 from the radiating patch, the distance d 2 being different from the distance d 1 .

2. The antenna of claim 1 , wherein the radiating patch has a length in one direction that is longer than its length in a vertical direction.

3. The antenna of claim 1 , further comprising at least one additional radiating patch disposed on a top surface of the insulating substrate.

4. 2. The antenna of claim 1, wherein the radiating patch has a truncated corner on the side facing the electrically floating patch.

5. The antenna of claim 1 , further comprising a parasitic patch disposed above the radiating patch.

6. The antenna of claim 5 , wherein the parasitic patch is larger than the radiating patch.

7. 2. The antenna of claim 1, further comprising a first feed line having a termination aligned below the first delay line and a second feed line having a termination aligned below the second delay line, the ground plane comprising a first window aligned with a termination of the first feed line and a second window aligned with a termination of the second feed line.

8. 1. An array antenna, comprising: An insulating substrate; a plurality of radiating patches disposed on a top surface of the insulating substrate; a plurality of first vias formed in the insulating substrate, each of the first vias being filled with a conductive material and each of the first vias being in contact with one of the radiating patches; a plurality of coupling patches disposed on a top surface of the insulating substrate, each of the coupling patches being spaced a distance d from one of the radiating patches, thereby forming a respective capacitor with one of the radiating patches; a plurality of second vias formed in the insulating substrate, each of the second vias being filled with a conductive material and each of the second vias being in electrical contact with one of the coupling patches; a plurality of first delay lines, each of which is connected to one of the first vias; a plurality of first control lines, each connected to a voltage source and each connected to one of the first delay lines; a plurality of second delay lines, each of which is connected to one of the second vias; a plurality of second control lines, each connected to the voltage supply and each connected to one of the second delay lines; a plurality of inductive-capacitive (LC) structures, each of which is coupled to one of the plurality of radiating patches, each of the plurality of inductive-capacitive structures being disposed on a top surface of the insulating substrate and spaced a distance d from a respective one of the radiating patches; ２ a neighboring patch disposed on the opposite side of each of said coupling patches, said spacing d 2 being different from spacing d 1 ; and a variable dielectric constant (VDC) plate disposed under the insulating substrate; An array antenna comprising:

9. moreover, a plurality of first RF feed lines, each of which couples RF energy to a respective one of the plurality of first delay lines; 9. The array antenna of claim 8, comprising: a plurality of second RF feed lines, each of which couples RF energy to a respective one of the plurality of second delay lines.

10. 9. The array antenna of claim 8, wherein the length of said adjacent patch is shorter than the side of the corresponding radiating patch.

11. 11. The array antenna of claim 10, wherein the proximity patch is insulated from any other conductive parts of the array antenna.

12. 9. The array antenna of claim 8, further comprising a second VDC plate, said ground plane being sandwiched between said VDC plate and said second VDC plate.

13. 10. The array antenna of claim 9, wherein the ground plane comprises a plurality of windows, each aligned with an end of one of the plurality of first delay lines.

14. 9. The array antenna of claim 8, further comprising a plurality of parasitic patches, each of which is disposed on a corresponding one of said plurality of radiating patches, each of said parasitic patches having the same shape but larger dimensions as said corresponding radiating patch.

15. The array antenna according to claim 14 , wherein the length of each of the radiating patches in one direction is longer than its length in a vertical direction.

16. 16. The array antenna of claim 15, wherein each of said radiating patches is pseudo-rectangular. 。

17. 9. The array antenna of claim 8, wherein each of the adjacent patches is electrically DC isolated from the voltage source.

18. moreover, a plurality of first feed lines, each having a termination aligned beneath one of the plurality of first delay lines; a plurality of second feed lines, each having a termination aligned beneath one of the plurality of second delay lines; 9. The array antenna of claim 8, wherein the ground plane comprises a plurality of first windows, each aligned with an end of a first feed line, and a plurality of second windows, each aligned with an end of the second feed line.

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