Patent Description:
One of the requirements for future cellular communications (e.g. <NUM> communication networks) is the provision of antennas that include low-profile phased arrays with extremely wide frequency bandwidth and wide angular scanning range. However, conventional phased arrays comprising multiple resonant radiating elements tends to have limited frequency bandwidth due to inherent bandwidth limitations of resonant radiating elements.

To overcome the problem of bandwidth limitation, a concept of connected arrays or tightly coupled dipole array, has been widely explored. The concept uses closely spaced dipoles to approximate continuous Wheeler current sheet for ultra-wideband performance. Such arrays are capable of operating over a very broad bandwidth and over a wide-scan angular volume. However, tightly coupled dipole array assumes an idealized delta-gap between closely spaced dipole sources as excitation.

It is to be noted that performance of such arrays relies on the realization of a broadband complex feed network, which is typically problematic and requires very long design cycles. Furthermore, coupling between radiating elements of this type of array is relatively high due to closely spaced elements. As a result, efficiency of such arrays often falls quickly over frequency bandwidth as beam scanning angle increases. To this end, there is an interest in developing a low-cost antenna structure with a low profile and low-complexity feed network. The document <CIT> shows artificial magnetic conductor antennas with shielded feed lines. The document <CIT> shows a beam-steered wide bandwidth electromagnetic band gap antenna. The document <CIT> shows a dual polarized antenna, especially a multiple-resonant-mode dual polarized antenna.

The present disclosure generally provides an antenna comprising: a plurality of Composite Right Left Handed (CRLH) magneto-electric unit-cell based structures, each CRLH magneto-electric unit-cell based structure comprising: a ground electrode for common electrical contacts; a first coaxial connector and a second coaxial connector, a first end of the first coaxial connector and a first end of the second coaxial connector connected to the ground electrode; a first ground surface and a second ground surface, the first ground surface connected to a second end of the first coaxial connector and the second ground surface connected to a second end of the second coaxial connector; a coaxial line included in the second coaxial connector; a microstrip feed line connected to the coaxial line and electromagnetically coupled with the first and the second ground surfaces; and a first non-resonant meta-surface patch and a second non-resonant meta-surface patch, each of the first and second non-resonant meta-surface patches printed on a dielectric material and placed above a series-capacitor gap between the first ground surface and the second ground surface and electromagnetically coupled to the first ground surface and the second ground surface.

In accordance with other aspects of the present disclosure, the antenna, wherein the first coaxial connector includes a second coaxial line.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein a radio frequency signal traversing in the microstrip feed line is configured to induce a tangential electric field in the series-capacitor gap resulting in a magnetic radiating source; the radio frequency signal is configured to induce an electric current in the microstrip feed line and the first ground surfaces resulting in an electric radiating source; and the magnetic radiating source and the electric radiating source form a magnetic-electric radiating element.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein the plurality of CRLH magneto-electric unit-cell based structures are separated from each other by a distance less than λ/<NUM>, where λ is a wavelength of a radio frequency signal fed to the microstrip feed line via the coaxial line.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein a width of the first non-resonant meta-surface patch and the second non-resonant meta-surface patch is less than λ/<NUM>, where λ is a wavelength of a radio frequency signal fed to the microstrip feed line via the coaxial line.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein the first coaxial connector and the second coaxial connector are separated from each other by a distance less than λ/<NUM>, where λ is a wavelength of a radio frequency signal fed to the microstrip feed line via the coaxial line.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein the first ground surface and the second ground surface have a tuning slot for RF tuning.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein the ground electrode is a ground perfect electric conductor.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein the plurality of CRLH magneto-electric unit-cell based structures are arranged as one-dimensional phased array structure.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein the plurality of CRLH magneto-electric unit-cell based structures are arranged as two-dimensional phased array structure.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein the first ground surface and second ground surface are arranged as a bow-tie capacitive structure.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein the first coaxial connector and the second coaxial connector are arranged as a shunt inductor structure.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein the plurality of CRLH magneto-electric unit-cell based structures are operated in evanescent mode.

In accordance with other or any previous aspects of the present disclosure, the antenna, wherein the first non-resonant meta-surface patch and the second non-resonant meta-surface patch provide impedance matching.

In accordance with other or any previous aspects of the present disclosure, the antenna is configured to provide a scan range of +/-<NUM> deg.

In accordance with other or any previous aspects of the present disclosure, the antenna, is configured to provide a bandwidth up to <NUM>.

In accordance with other broad aspects of the present disclosure there is provided a method of forming an antenna structure comprising: forming a plurality of Composite Right Left Handed (CRLH) magneto-electric unit-cell based structures, where forming each CRLH magneto-electric unit-cell based structure comprises: forming a ground electrode for common electrical contacts; forming a first coaxial connector and a second coaxial connector, a first end of the first coaxial connector and a first end of the second coaxial connector are connected to the ground electrode; forming a first ground surface and a second ground surface connected to a second end of the first coaxial connector and a second end of the second coaxial connector respectively; forming a coaxial line included in the second coaxial connector; forming a microstrip feed line connected to the coaxial line and electromagnetically coupled with the first and the second ground surfaces; and forming a first non-resonant meta-surface patch and a second non-resonant meta-surface patch disposed over a dielectric material and placed above a series-capacitor gap between the first ground surface and the second ground surface and electromagnetically coupled to the first ground surface and the second ground surface.

It is to be understood that throughout the appended drawings and corresponding descriptions, like features are identified by like reference characters. Furthermore, it is also to be understood that the drawings and ensuing descriptions are intended for illustrative purposes only and that such disclosures do not provide a limitation on the scope of the claims.

The instant disclosure is directed to address at least some of the deficiencies of the current technology. In particular, the instant disclosure describes a Composite Right Left Handed (CRLH) magneto-electric unit-cell based structure for antenna and system.

In the context of directional references described herein such as "front", "rear", "up", "down", "horizontal", "top", "bottom", "side" and the like are used purely for convenience of description and do not limit the scope of the present disclosure. Furthermore, any dimensions provided herein are presented merely by way of an example and unless otherwise specified do not limit the scope of the disclosure. Furthermore, geometric terms such as "straight", "flat", "curved", "point" and the like are not intended to limit the disclosure any specific level of geometric precision, but should instead be understood in the context of the disclosure, taking into account normal manufacturing tolerances, as well as functional requirements as understood by a person skilled in the art.

In the context of the present specification, unless provided expressly otherwise, the words "first", "second", "third", etc. have been used as adjectives only for the purpose of allowing for distinction between the nouns that they modify from one another, and not for the purpose of describing any particular relationship between those nouns. Thus, for example, it should be understood that, the use of the terms "first processor" and "third processor" is not intended to imply any particular order, type, chronology, hierarchy or ranking (for example) of/between the server, nor is their use (by itself) intended to imply that any "second server" must necessarily exist in any given situation. Further, as is discussed herein in other contexts, reference to a "first" element and a "second" element does not preclude the two elements from being the same actual real-world element. Thus, for example, in some instances, a "first" server and a "second" server may be the same software and/or hardware, in other cases they may be different software and/or hardware.

It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly or indirectly connected or coupled to the other element or intervening elements that may be present.

The terminology used herein is only intended to describe particular representative embodiments and is not intended to be limiting of the present technology.

Implementations of the present technology each have at least one of the above-mentioned objects and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and/or may satisfy other objects not specifically recited herein.

The examples and conditional language recited herein are principally intended to aid the reader in understanding the principles of the present technology and not to limit its scope to such specifically recited examples and conditions. It will be appreciated that those skilled in the art may devise various arrangements which, although not explicitly described or shown herein, nonetheless embody the principles of the present technology and are included within its scope.

Moreover, all statements herein reciting principles, aspects, and implementations of the present technology, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof, whether they are currently known or developed in the future.

The functions of the various elements shown in the figures, including any functional block labeled as a "processor" or a "graphics processing unit", may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. In some embodiments of the present technology, the processor may be a general purpose processor, such as a central processing unit (CPU) or a processor dedicated to a specific purpose, such as a graphics processing unit (GPU). Moreover, explicit use of the term "processor" or "controller" should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read-only memory (ROM) for storing software, random access memory (RAM), and non-volatile storage.

Software modules, or simply modules, or units which are implied to be software, may be represented herein as any combination of flowchart elements or other elements indicating performance of process steps and/or textual description.

With these fundamentals in place, the instant disclosure is directed to address at least some of the deficiencies of the current technology. In particular, the instant disclosure describes a CRLH magneto-electric unit-cell based structure for antenna and system.

As previously discussed, the concept of connected arrays, or tightly coupled dipole arrays uses closely spaced dipoles to approximate continuous Wheeler current sheet for ultra-wideband performance. Although, such arrays are capable of operating over a very broad bandwidth and over a wide-scan angular volume, performance of such arrays relies on the realization of a broadband complex feed network. To this end, the present disclosure discloses an alternative ultra-wideband phased array concept based on Composite Right Left Handed (CRLH) transmission structure operated in evanescent-mode that provides a low-cost antenna structure with a low profile and low-complexity feed network. In so doing, surface wave propagation between magnetic-electric radiating elements of the phased array is controlled through evanescent-mode propagation in a CRLH transmission structure. The CRLH transmission structure-based phased array allows a limited or weak coupling among CRLH unit cells, which results in ultra-wideband operations.

Further to the ultra-wideband operations, the CRLH transmission structure-based phased array also provides a wide angular scanning range. In certain embodiments, the array structure may be a series of magneto-electric radiators that are a combination of alternating linear dipole and stacked patches. The dipole array produces a continuous electric current and the slot-patch array produces a series of magnetic current. This type of array structure is capable of providing flexible beam scanning with relatively wide scanning angle over an extremely wide frequency bandwidth and with high radiation efficiency.

With this said, <FIG> depicts an isometric view of an example of high-level structural diagram of a CRLH magneto-electric unit-cell based structure <NUM>, in accordance with various embodiments of the present disclosure. It is to be noted that the CRLH magneto-electric unit-cell based structure <NUM> may include two CRLH magneto-electric unit-cells. It is to be noted that various implementations of the present disclosure may include a plurality of CRLH magneto-electric unit-cell based structures <NUM> arranged in one or two dimensions. As shown, the CRLH magneto-electric unit-cell based structure <NUM> may include a ground electrode <NUM> for common electrical contacts. In certain embodiments, the ground electrode <NUM> may be a ground perfect electric conductor (PEC). In this context, "perfect electric conductor" means that the conductivity of the material used to create the ground electrode is sufficient to provide substantially equal potential throughout, with sheet resistance low enough to be negligible compared to other effects.

The CRLH magneto-electric unit-cell based structure <NUM> further includes a first coaxial connector <NUM>-<NUM> and a second coaxial connector <NUM>-<NUM> (also referred to as coax tubes). In certain embodiments, an outer shield of the two coaxial connectors <NUM>-<NUM> and <NUM>-<NUM> may act as shunt inductors. The bottom of the two coaxial connectors <NUM>-<NUM> and <NUM>-<NUM> may be connected to the ground electrode <NUM> and the top may be connected to ground surfaces <NUM>-<NUM> and <NUM>-<NUM> respectively. In certain embodiments, the ground surfaces <NUM>-<NUM> and <NUM>-<NUM> may be designed as bow-tie shaped caps. Further, in certain embodiments, each of the ground surfaces <NUM>-<NUM> and <NUM>-<NUM> may symmetrically surround the two coaxial connectors <NUM>-<NUM> and <NUM>-<NUM> respectively. In yet further embodiments, the two ground surfaces <NUM>-<NUM> and <NUM>-<NUM> may be supported by a dielectric substrate <NUM>. It is to be noted that the first coaxial connector <NUM>-<NUM> and the ground surface <NUM>-<NUM> may represent first CRLH magneto-electric unit-cell and the second coaxial connector <NUM>-<NUM> and the ground surface <NUM>-<NUM> may represent second CRLH magneto-electric unit-cell.

In certain embodiments, the two coaxial connectors <NUM>-<NUM> and <NUM>-<NUM> may include polytetrafluoroethylene (PTFE) filled coaxial lines. For the purpose of simplicity, only the coaxial connector <NUM>-<NUM> has been illustrated with the PTFE filled coaxial line <NUM>. As shown in enlarged view <NUM> of a portion of the CRLH magneto-electric unit-cell based structure <NUM>, the PTFE filled coaxial line <NUM> includes a central conductor <NUM>, in which a microstrip feed line <NUM> may be connected to the central conductor <NUM>. The microstrip feed line <NUM> may traverse through the series-capacitor gap <NUM> between the two ground surfaces <NUM>-<NUM> and <NUM>-<NUM>. It is to be noted that the far end of the microstrip feed line <NUM> may not be physically connected to the coaxial connector <NUM>-<NUM> and the two ground surfaces <NUM>-<NUM> and <NUM>-<NUM>. Rather, the microstrip feed line <NUM> may be electromagnetically coupled to the coaxial connector <NUM>-<NUM> and the two ground surfaces <NUM>-<NUM> and <NUM>-<NUM>. In certain embodiments, each of the ground surfaces <NUM>-<NUM> and <NUM>-<NUM> may have a tuning slot <NUM> for radio frequency (RF) tuning.

It is to be noted that a similar arrangement (not illustrated in the <FIG>) may be associated with the coaxial connector <NUM>-<NUM>. The coaxial connector <NUM>-<NUM> may also include the PTFE filled coaxial line with the central conductor to which the microstrip feed line may be connected to the central conductor. Such microstrip feed line may traverse through the series-capacitor gap between the ground surface <NUM>-<NUM> and a similar ground surface placed at a distance less than λ/<NUM> to the left of the coaxial connector <NUM>-<NUM>.

The CRLH magneto-electric unit-cell based structure <NUM> further includes a non-resonant meta-surface top patch <NUM>-<NUM> and a non-resonant meta-surface bottom patch <NUM>-<NUM>. The two patches <NUM>-<NUM> and <NUM>-<NUM> are not directly connected with each other nor are they connected to the ground surfaces <NUM>-<NUM> and <NUM>-<NUM>. Also, in certain embodiments, the two patches <NUM>-<NUM> and <NUM>-<NUM> may be disposed, i.e. by printing, evaporation, or electroplating, etc., on a dielectric material.

<FIG> depicts a top view <NUM> of an example of high-level structural diagram of the CRLH magneto-electric unit-cell based structure <NUM>, in accordance with various embodiments of the present disclosure. <FIG> depicts a side view <NUM> of an example of high-level structural diagram of the CRLH magneto-electric unit-cell based structure <NUM>, in accordance with various embodiments of the present disclosure.

<FIG> depicts an equivalent circuit diagram <NUM> of the CRLH magneto-electric unit-cell based structure <NUM>, in accordance with various embodiments of present disclosure. In particular, the left portion of the equivalent circuit diagram <NUM> may represent an equivalent circuit diagram <NUM> associated with the ground surface <NUM>-<NUM>, the coaxial connector <NUM>-<NUM>, and the ground electrode <NUM>. The right portion of the equivalent circuit diagram <NUM> may represent an equivalent circuit diagram <NUM> associated with the ground surface <NUM>-<NUM>, the coaxial connector <NUM>-<NUM>, and the ground electrode <NUM>. The center portion of the equivalent diagram <NUM> may represent an equivalent circuit diagram <NUM> associated with the microstrip feed line <NUM> and the series-capacitor gap <NUM>.

In certain embodiments, a CRLH transmission structure may be constructed by cascading multiple CRLH magneto-electric unit-cells including the coaxial connectors similar to the coaxial connector <NUM>-<NUM> and/or <NUM>-<NUM> and ground surfaces similar to the ground surfaces <NUM>-<NUM> and/or <NUM>-<NUM> may be placed at a distance less than λ/<NUM> from each other. Further, in between the ground surfaces the non-resonant meta-surface top patches similar to the non-resonant meta-surface top patches <NUM>-<NUM> and <NUM>-<NUM> may be placed.

The coaxial connectors associated with the multiple CRLH magneto-electric unit-cells may also include the PTFE filled coaxial lines with the central conductor to which the microstrip feed line may be connected to the central conductor. Such microstrip feed line may traverse through the series-capacitor gap from right to left or right to left (depending on the configuration) between the adjacent ground surfaces. The above mentioned arrangements may be similar to as discussed in context of the CRLH magneto-electric unit-cell based structure <NUM>.

<FIG> depicts a top view <NUM> and a side view <NUM> of an example of high-level structural diagram of CRLH transmission structure <NUM> constructed by cascading multiple CRLH magneto-electric unit-cell structures <NUM>, in accordance with various embodiments of the present disclosure.

In certain embodiments, the CRLH transmission structure <NUM> may include series capacitors and shunt inductors. The series capacitors may be constructed by placing the multiple ground surfaces (such as ground surfaces <NUM>-<NUM> and <NUM>-<NUM>) in close proximity along the long axis of the CRLH transmission structure <NUM>. The shunt inductors are constructed by connecting the multiple ground surfaces (such as ground surfaces <NUM>-<NUM> and <NUM>-<NUM>) to the ground electrode <NUM> via multiple coaxial connectors (such as coaxial connectors <NUM>-<NUM>, and <NUM>-<NUM>).

Further, in certain embodiments, magneto-electric radiating sources may be formed at the series-capacitor gaps (such as the series-capacitor gap <NUM>) between the multiple ground surfaces with the microstrip feed lines (such as microstrip feed line <NUM>) traversing the series-capacitor gaps. In certain embodiments, the microstrip feed lines may be placed at a small distance just above the ground surfaces.

The CRLH transmission structure <NUM> may include multiple non-resonant meta-surface patches (such as non-resonant meta-surface patches <NUM>-<NUM> and <NUM>-<NUM>) placed above the series-capacitor gaps. In certain embodiments, the non-resonant meta-surface top patches may provide impedance matching. In other embodiments, the size of each of the non-resonant meta-surface top patches may be smaller than half-wavelength of their resonant frequency and are not operated in resonant mode. The patches primarily introduce reactive elements for the purpose of impedance matching of excitation sources. In certain embodiments, the microstrip feed lines may be fed with RF signal using the PTFE filled coaxial lines (such as, the PTFE filled coaxial line <NUM>) embedded in the coaxial connectors.

As the RF signal propagates through the microstrip feed lines, the RF signal may induce tangential electric fields across the series-capacitor gaps which may be characterized as an equivalent magnetic current at the series-capacitor gaps which, in turn, may then induce an electric current along the ground surface and the coaxial connector as the wave propagates further down the CRLH transmission structure <NUM>. As a result, both electric and magnetic currents forming an EM field may be excited along the CRLH transmission structure <NUM>.

It is to be noted that the RF signal induces a displacement current in the series-capacitor gaps that results in a magnetic radiating source while the RF signal induces the electric current in the microstrip feed line and the ground surfaces that results in an electric radiating source. Together, the magnetic radiating source and the electric radiating source form a magnetic-electric radiating element.

It is to be noted that the EM field excited in one CRLH magneto-electric unit-cell based structure <NUM> may spread over to a number of CRLH magneto-electric unit-cell based structures <NUM> in the CRLH transmission structure <NUM>. The effective distance of the EM field propagation within the CRLH transmission structure <NUM> may depend on the designed characteristics of each CRLH magneto-electric unit-cell based structures <NUM>. Since the CRLH magneto-electric unit-cell based structures <NUM> are designed to operate in evanescent modes, couplings between them are relatively low as compared to that of a tightly coupled dipole array. To this end, the CRLH transmission structure <NUM> may provide a lower return loss due to lower coupling among multiple CRLH magneto-electric unit-cell based structures <NUM> through evanescent mode propagation of EM field. Consequently, the CRLH transmission structure <NUM> provides a higher radiating efficiency over a wide scanning angle. Furthermore, the CRLH transmission structure <NUM> may not require a complex, broadband feed structure and the simple PTFE filled coaxial line <NUM> may be used to feed the microstrip feed line <NUM>.

In certain embodiments, the CRLH transmission structure <NUM> may be characterized by the following resonant frequencies: <MAT> <MAT> <MAT> <MAT> <MAT>.

Where, the parameters CL, CR, LL, LR, are the right- and left-hand capacitances and inductances, which are determined by the geometries of the CRLH magneto-electric unit-cell based structure <NUM>. The principal concept of the design is to operate the CRLH magneto-electric unit-cell based structures <NUM> in the zones where wave propagation in the CRLH transmission structure <NUM> is in evanescent mode.

Thus, by virtue of the CRLH transmission structure <NUM>, attenuation factors between radiating elements may be controlled such that effective mutual couplings between radiating elements are limited to only a few elements. Also, the CRLH transmission structure <NUM> allows increase in operating bandwidth of the array through suppressed surface wave and low mutual coupling which results in low directivity loss.

<FIG> depicts a general dispersion diagram and bands of the operation of the CRLH transmission structure <NUM>, in accordance with various embodiments of the present disclosure. The CRLH transmission structure <NUM> may be designed to operate in the frequency band gap between the series resonance frequency (ωSE) and the shunt resonance frequency (ωSH). This gap is due to the difference between series and shunt resonance frequencies (ωse,ωsh). Signal propagations in this region is evanescent in nature, i.e., signals get attenuated significantly but not completely blocked as in the RH and LH stop-band regions.

A conventional CRLH LWA is designed for balanced case (ωse=ωsh) and aimed to suppress this band-gap. On the contrary, here the band-gap region is exploited for broadband phased array operation using distributed sources. Since the attenuation factor (α) of wave propagations is relatively large in this region, mutual couplings between array feeds are minimized and potential reflections from finite array edges are suppressed. A wide band-gap can be achieved by using CRLH magneto-electric unit-cell based structure <NUM> with a relatively large series inductance (LL) and a small series capacitance (CL), which can be achieved using a planar dipole or monopole in series with a relatively wide series-capacitor gap <NUM> between the CRLH magneto-electric unit-cell based structure <NUM>. Notice that the series-capacitor gap <NUM> should be relatively wide in terms of capacitance, but not overly wide to result in isolated radiating elements.

As previously discussed, the CRLH transmission structure <NUM> may provide ultra broadband characteristics using multiple CRLH magneto-electric unit-cell based structures <NUM> placed at a spacing of less than half-wavelength along with multi-layer of broadband impedance matching meta-surfaces i.e. the non-resonant meta-surface top patches <NUM>-<NUM> and the non-resonant meta-surface bottom patches <NUM>-<NUM>.

<FIG> depicts an equivalent impedance matching circuit diagram <NUM> of the CRLH transmission structure <NUM>, in accordance with various embodiments of the present disclosure. As shown, the equivalent impedance matching circuit diagram <NUM> includes an equivalent of radiating elements backed by the equivalent ground electrode <NUM> on the right side and equivalent of non-resonant meta-surface top patches <NUM>-<NUM> and the non-resonant meta-surface bottom patches <NUM>-<NUM> on the left side printed on the dielectric material. In one embodiment, the dielectric material in between the patches <NUM>-<NUM> and <NUM>-<NUM> and the dielectric material between the bottom patch <NUM>-<NUM> and the radiating elements may have a same dielectric constant and equals to ε<NUM>. In another embodiment, the dielectric material in between the patches <NUM>-<NUM> and <NUM>-<NUM> and the dielectric material between the bottom patch <NUM>-<NUM> and the radiating elements may have different dielectric constants equals to ε<NUM> and ε<NUM> respectively.

The total impedance at the plane of the radiating elements may be a sum of the impedance of the radiating elements and parallel of all discontinuity impedances, including the complex element impedance, transformed impedances of the ground electrode <NUM>, and transformed impedances of capacitive meta-surfaces i.e. the patches <NUM>-<NUM> and <NUM>-<NUM>. In one embodiment, the total impedance may be represented as: <MAT>.

Where, ZA is the impedance of the radiating elements and may be represented as ZA = RA + jXA, Zc is the transformed impedances of capacitive meta-surface patches <NUM>-<NUM> and <NUM>-<NUM> and may be represented as Zc = Zc<NUM>(d<NUM>)//( Zc<NUM>(d<NUM>)), and ZGND is the transformed impedances of the ground electrode <NUM> and may be represented as ZGND = ZPEC(d<NUM>).

It is to be noted that the operational characteristics (e.g. impedances) of the radiating elements and the patches <NUM>-<NUM> and <NUM>-<NUM> tend to cancel out the purely reactive impedance of the ground electrode <NUM>. As a result, the radiating elements provide a relatively wide frequency bandwidth. In certain embodiments, the impedance of the radiating elements may be tuned to a real value over a relatively wide frequency bandwidth by setting the ground electrode <NUM> and the patches <NUM>-<NUM> and <NUM>-<NUM> at proper locations d<NUM>, d<NUM> and d<NUM> respectively. The amplitudes and phases of the complex impedances, Zc1 and Zc2 , associated with the patches <NUM>-<NUM> and <NUM>-<NUM> respectively may be adjusted using geometries of the patches <NUM>-<NUM> and <NUM>-<NUM>.

In a non-limiting embodiment of the present disclosure, Table I provides a critical example of dimensions of the example to build or form the CRLH magneto-electric unit-cell based structure <NUM>.

Table II provides calculated circuit parameters and resonant frequencies of the corresponding CRLH transmission structure <NUM>. In one non-limiting embodiment, as shown in Table II, the CRLH transmission structure <NUM> may be designed to be a stopband structure with transition frequency near <NUM>, which has a <NUM>nd harmonic frequency at about <NUM>.

<FIG> illustrates the effect of electric and magnetic field excitation of the CRLH magneto-electric unit-cell based structure <NUM> on other CRLH magneto-electric unit-cell based structures <NUM> in the CRLH transmission structure <NUM>, in accordance with various embodiments of present disclosure. As shown if the CRLH magneto-electric unit-cell based structure <NUM> is excited with the electric and magnetic field, in certain embodiments, the mutual coupling effect may be limited to <NUM>-<NUM> adjacent CRLH magneto-electric unit-cell based structures <NUM>.

<FIG> depicts a representative outcome <NUM> corresponding to a mutual coupling between a first feed source for frequency between <NUM> to <NUM> feeding one CRLH magneto-electric unit-cell based structure <NUM> and other feed sources for frequency between <NUM> to <NUM> feeding other CRLH magneto-electric unit-cell based structures <NUM> in an array of <NUM> CRLH magneto-electric unit-cell based structures <NUM>, in accordance with various embodiments of present disclosure. As shown, mutual coupling between the radiating elements is dropped below -<NUM> dB after the fifth radiating element away from the active radiating element. In certain embodiments, near the <NUM>nd harmonic frequency of <NUM> to <NUM>, the mutual coupling further reduced significantly as illustrated.

<FIG> illustrates a representative outcome <NUM> corresponding to VSWR (S11) of the CRLH transmission structure <NUM> including an array of <NUM> CRLH magneto-electric unit-cell based structures <NUM>, in accordance with various embodiments of the present disclosure. As illustrated, the array of <NUM> CRLH magneto-electric unit-cell based structures <NUM> may achieve a VSWR <<NUM> for frequency from <NUM> to <NUM>, which has a bandwidth of about <NUM>:<NUM>, or a fractional bandwidth of <NUM>%.

It is to be noted that in such a configuration with radiating elements in close proximity, the actual return power losses may also depend on the active impedance rather the passive S11 parameter of individual radiating elements. This is because, unlike in a single antenna case, the actual return power losses may be due to the active impedance of the array of radiating elements including mutual coupling. Also, the active impedance of the array of radiating elements may be significantly different from that of isolated elements (S11), depending on radiating element spacing and scan angle of the array of radiating elements.

<FIG> depicts a representative outcome <NUM> to Active VSWR of the CRLH transmission structure <NUM> including an array of <NUM> CRLH magneto-electric unit-cell based structures <NUM> for various scan angles for frequency between <NUM> and <NUM>, in accordance with various embodiments of the present disclosure. As depicted, the magnitude of the Active VSWR <<NUM> may be achieved for the frequency range between <NUM> to <NUM> for scan angles from <NUM> deg to <NUM> deg.

<FIG> illustrates a representative outcome <NUM> corresponding to directivity loss of the CRLH transmission structure <NUM> due to active VSWR for scan angle between <NUM> deg to <NUM> deg, in accordance with various embodiments of the present disclosure. As illustrated, in certain embodiments, the directivity loss of the CRLH transmission structure <NUM> due to the active VSWR may be within -<NUM> dB (-<NUM> dB active return loss) between <NUM> to <NUM> for scan angles up to <NUM> deg.

<FIG> depict representative E-plane co-polar and cross-polar radiation patterns of the CRLH transmission structure <NUM> including an array of <NUM> CRLH magneto-electric unit-cell based structures <NUM> for various scan angles, in accordance with various embodiments of the present disclosure. In particular, <FIG> depicts E-plane co-polar and cross-polar radiation patterns <NUM> for various scan angles corresponding to signal having frequency of <NUM>. <FIG> depicts E-plane co-polar and cross-polar radiation patterns <NUM> for various scan angles corresponding to signal having frequency of <NUM>. <FIG> depicts E-plane co-polar and cross-polar radiation patterns <NUM> for various scan angles corresponding to signal having frequency of <NUM>.

<FIG> illustrates representative H-plane co-polar and cross-polar radiation patterns <NUM> of the CRLH transmission structure <NUM> including an array of <NUM> CRLH magneto-electric unit-cell based structures <NUM> for various frequencies corresponding to scan angle equals to <NUM> deg, in accordance with various embodiments of the present disclosure.

An incredibly low cross-polarized field, below -<NUM> dB within the main lobe, for all scan angles has been observed both for E- and H-plane patterns in various embodiments.

It is to be noted that the broadband characteristics of the CRLH transmission structure <NUM> is even more evident at higher frequencies. <FIG> illustrates a representative passive VSWR versus ultra-wideband (UWB) frequency response <NUM> for the CRLH transmission structure <NUM> including an array of <NUM> CRLH magneto-electric unit-cell based structures <NUM>, in accordance with various embodiments of the present disclosure. As shown, in certain embodiments, the array of <NUM> CRLH magneto-electric unit-cell based structures <NUM> has an impedance bandwidth of <NUM>:<NUM> (<NUM> to <NUM>) with VSWR<<NUM>, which is <NUM>% of fractional frequency bandwidth.

<FIG> illustrates a representative active VSWR versus UWB frequency response <NUM> for the CRLH transmission structure <NUM> including an array of <NUM> CRLH magneto-electric unit-cell based structures <NUM>, in accordance with various embodiments of the present disclosure. As shown, in certain embodiments, the array of <NUM> CRLH magneto-electric unit-cell based structures <NUM> may achieve a frequency bandwidth of more than <NUM>% (<NUM> to <NUM>) with active VSWR of <<NUM> for scan angles up to <NUM> deg. Thus, in certain embodiments, the CRLH transmission structure <NUM> may be configured to provide a bandwidth up to <NUM>.

<FIG> depict representative radiation patterns for the CRLH transmission structure <NUM> including an array of <NUM> CRLH magneto-electric unit-cell based structures <NUM> operated at UWB frequency, in accordance with various embodiments of the present disclosure. In particular, <FIG> depicts radiation patterns <NUM> for various scan angles corresponding to signal having frequency of <NUM>. <FIG> depicts radiation patterns <NUM> for various scan angles corresponding to signal having frequency of <NUM>. <FIG> depicts radiation patterns <NUM> for various scan angles corresponding to signal having frequency of <NUM>. <FIG> depicts radiation patterns <NUM> for various scan angles corresponding to signal having frequency of <NUM>.

It is to be noted that a conventional phased array including a tightly coupled dipole array has a Cos(θ) of scan loss factor, which gives over <NUM> dB of scan loss at <NUM> deg to <NUM> deg of scan angle. However, in certain embodiments, the scan loss may be less than <NUM> dB up to <NUM> deg of scan angles with the CRLH transmission structure <NUM>. To this end, in certain embodiments, the CRLH transmission structure <NUM> may be configured to provide a scan range of +/-<NUM> deg.

<FIG> illustrates a representative outcome <NUM> corresponding to one CRLH magneto-electric unit-cell based structure <NUM> in the CRLH transmission structure <NUM>, in accordance with various embodiments of present disclosure. As shown, due to small dimension of the CRLH magneto-electric unit-cell based structure <NUM>, each magneto-electric unit-cell has a relatively broad radiation pattern and, as a result, scan loss may be less than <NUM> dB up to <NUM> deg of scan angles.

It to be noted that, in certain embodiments, the CRLH transmission structure <NUM> may be expanded to two-dimensional dual-polarized phased array structure. <FIG> depicts a top view of an example of high-level <NUM>×<NUM> two-dimensional structural diagram of CRLH transmission structure <NUM> constructed by cascading multiple CRLH magneto-electric unit-cell based structures <NUM>, in accordance with various embodiments of the present disclosure.

Equally notable, the disclosed structural embodiments of the CRLH transmission structure <NUM> provides a low-cost antenna structure with a low profile and low-complexity feed that may be operated at ultra-wideband frequency bandwidth and capable of providing flexible beam scanning with relatively wide scanning angle. To this end, the CRLH transmission structure <NUM> may be implemented in a variety of devices, such as, for example, mobile communication devices, satellite communication devices, wireless routers, base stations, access points, a client terminal in a wireless communication network and other wireless and telecommunication devices and applications. Such devices may be employed in a stationary or mobile environment and may be implemented for communications within <NUM> communication networks or other wireless communication networks.

<FIG> is a schematic diagram of an example wireless communication device <NUM>, in which examples of the CRLH transmission structure <NUM> described herein may be used, in accordance with the embodiments of the present disclosure. For example, the wireless communication device <NUM> may be a base station, an access point, or a client terminal in a wireless communication network or the like. The wireless communication device <NUM> may be used for communications within <NUM> communication networks or other wireless communication networks. Although <FIG> shows a single instance of each component, there may be multiple instances of each component in the wireless communication device <NUM>. The wireless communication device <NUM> may be implemented using parallel and/or distributed architecture.

The wireless communication device <NUM> may include one or more processing devices <NUM>, such as a processor, a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a dedicated logic circuitry, or combinations thereof. The wireless communication device <NUM> may also include one or more optional input/output (I/O) interfaces <NUM>, which may enable interfacing with one or more optional input devices <NUM> and/or output devices <NUM>. The wireless communication device <NUM> may include one or more network interfaces <NUM> for wired or wireless communication with a network (e.g., an intranet, the Internet, a P2P network, a WAN and/or a LAN, and/or a Radio Access Network (RAN)) or other node. The network interface(s) <NUM> may include one or more interfaces to wired networks and wireless networks. Wired networks may make use of wired links (e.g., Ethernet cable). The network interface(s) <NUM> may provide wireless communication (e.g., full-duplex communications) via an example of the CRLH transmission structure <NUM>. The wireless communication device <NUM> may also include one or more storage units <NUM>, which may include a mass storage unit such as a solid state drive, a hard disk drive, a magnetic disk drive and/or an optical disk drive.

The wireless communication device <NUM> may include one or more memories <NUM> that can include a physical memory <NUM>, which may include a volatile or non-volatile memory (e.g., a flash memory, a random access memory (RAM), and/or a read-only memory (ROM)). The non-transitory memory(ies) <NUM> (as well as storage <NUM>) may store instructions for execution by the processing device(s) <NUM>. The memory(ies) <NUM> may include other software instructions, such as for implementing an operating system (OS), and other applications/functions. In some examples, one or more data sets and/or modules may be provided by an external memory (e.g., an external drive in wired or wireless communication with the wireless communication device <NUM>) or may be provided by a transitory or non-transitory computer-readable medium. Examples of non-transitory computer readable media include a RAM, a ROM, an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a CD-ROM, or other portable memory storage.

There may be a bus <NUM> providing communication among components of the wireless communication device <NUM>. The bus <NUM> may be any suitable bus architecture including, for example, a memory bus, a peripheral bus or a video bus. Optional input device(s) <NUM> (e.g., a keyboard, a mouse, a microphone, a touchscreen, and/or a keypad) and optional output device(s) <NUM> (e.g., a display, a speaker and/or a printer) are shown as external to the wireless communication device <NUM>, and connected to optional I/O interface <NUM>. In other examples, one or more of the input device(s) <NUM> and/or the output device(s) <NUM> may be included as a component of the wireless communication device <NUM>.

The processing device(s) <NUM> may be used to control communicate transmission/reception signals to/from the CRLH transmission structure <NUM>. The processing device(s) <NUM> may be used to control beam steering by the CRLH transmission structure <NUM>, for example by controlling the voltage applied to the isolated ground of the unit cells, for tuning the encapsulated liquid crystal. The processing device(s) <NUM> may also be used to control the phase of the phase variable lens, in order to steer the antenna beam over a 2D plane.

Claim 1:
An antenna comprising:
a plurality of Composite Right Left Handed, CRLH, magneto-electric unit-cell based structures (<NUM>), each CRLH magneto-electric unit-cell based structure (<NUM>) comprising:
a ground electrode (<NUM>) for common electrical contacts;
a first coaxial connector (<NUM>-<NUM>) and a second coaxial connector (<NUM>-<NUM>), a first end of the first coaxial connector (<NUM>-<NUM>) and a first end of the second coaxial connector (<NUM>-<NUM>) connected to the ground electrode (<NUM>);
a first ground surface (<NUM>-<NUM>) and a second ground surface (<NUM>-<NUM>), the first ground surface (<NUM>-<NUM>) connected to a second end of the first coaxial connector (<NUM>-<NUM>) and the second ground surface (<NUM>-<NUM>) connected to a second end of the second coaxial connector (<NUM>-<NUM>);
a coaxial line (<NUM>) included in the second coaxial connector (<NUM>-<NUM>);
a microstrip feed line (<NUM>) connected to the coaxial line (<NUM>) and electromagnetically coupled with the first (<NUM>-<NUM>) and the second ground surfaces (<NUM>-<NUM>); and
a first non-resonant meta-surface patch (<NUM>-<NUM>) and a second non-resonant meta-surface patch (<NUM>-<NUM>), each of the first (<NUM>-<NUM>) and second non-resonant meta-surface patches (<NUM>-<NUM>) printed on a dielectric material (<NUM>) and placed above a series-capacitor gap between the first ground surface (<NUM>-<NUM>) and the second ground surface (<NUM>-<NUM>) and electromagnetically coupled to the first ground surface (<NUM>-<NUM>) and the second ground surface (<NUM>-<NUM>).