Artificial magnetic conductor integrated mobile handset antenna with SAR reduction, adaptive radiation pattern control and gain improvement for satellite communications

Abstract

The invention relates to the integration of an antenna and an artificial magnetic conductor which is a significant innovation in mobile handset design. This combination not only optimizes performance for satellite communications by increasing antenna gain and EIRP but also ensures safety by reducing the SAR, making mobile handsets safer for users.

Description

TITLE OF THE INVENTIONArtificial Magnetic Conductor integrated mobile handset antenna with SAR reduction, adaptive radiation pattern control and gain improvement for satellite communications.CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] There are no related applications.FIELD OF THE INVENTION

[0002] The invention primarily focuses on creating and deploying an advanced antenna system tailored for constrained devices, such as mobile handsets. It aims to enhance the Effective Isotropic Radiated Power (EIRP) in the communication link between a handheld device and a satellite, while also reducing the Specific Absorption Rate (SAR) to ensure user safety.INTERPRETATION

[0003] As used in this specification and the claim(s), the following words / expressions have the meaning word indicated hereunder:1. Artificial Magnetic Conductor (AMC): A type of metamaterial that mimics the behavior of a perfect magnetic conductor, reflecting electromagnetic waves without phase reversal. AMCs are used to improve antenna performance by reducing surface wave propagation, increasing gain, and reducing SAR.2. Effective Isotropic Radiated Power (EIRP): A measure of the power radiated by an antenna in a particular direction compared to an isotropic antenna (an idealized antenna that radiates equally in all directions). EIRP is used to evaluate the strength of the signal transmitted by the antenna.3. Specific Absorption Rate (SAR): A measure of the rate at which the human body absorbs radiofrequency (RF) energy when exposed to an RF electromagnetic field. SAR is a critical parameter in ensuring the safety of mobile devices, particularly in minimizing exposure to RF energy.4. High Impedance Surface (HIS): A class of metamaterials engineered to have a high surface impedance over a certain frequency range. HIS structures prevent surface wavepropagation and are used in antennas to reflect electromagnetic waves without phase reversal.5. Frequency Selective Surface (FSS): A periodic surface that exhibits reflective or transmissive properties based on the frequency of the incident electromagnetic waves. FSS can be used in antenna systems to filter specific frequencies and improve overall performance.6. Metamaterials: Artificially structured materials engineered to exhibit properties not found in naturally occurring materials. Metamaterials can manipulate electromagnetic waves in novel ways, such as altering the phase, amplitude, or polarization.7. Meta Surface: A two-dimensional analog of metamaterials, consisting of periodic or quasi-periodic arrangements of subwavelength elements. Meta surfaces can manipulate electromagnetic waves to enhance radiation patterns, suppress surface waves, and reduce SAR.8. Circular Polarization: A type of electromagnetic wave polarization where the electric field rotates in a circular motion as the wave propagates. Circular polarization is beneficial in satellite communications for maintaining consistent signal quality regardless of orientation.9. Planar Inverted-F Antenna (PIFA): A type of low-profile antenna commonly used in mobile devices. PIFAs are compact and efficient, making them suitable for applications where space is limited, such as mobile handsets.10. Dielectric Substrate: An insulating material that can be polarized by an applied electric field. In antennas, dielectric substrates are used to reduce the size of the antenna by lowering the wavelength of the signal within the material, which also helps in reducing SAR.11. Electromagnetic Band Gap (EBG) Structure: A periodic arrangement that prevents the propagation of electromagnetic waves within a specific frequency range, creating a band gap. EBG structures are used in antennas to suppress unwanted surface waves and improve radiation performance.12. Beam Steering: The ability of an antenna system to dynamically change the direction of its radiation pattern. Beam steering is used in mobile handsets to focus the signal towards a satellite, enhancing communication efficiency.13. Quadrifilar Helix Antenna: A type of helical antenna used for satellite communications, characterized by four helices wound around a common axis. This antenna provides circular polarization and a wide beamwidth, making it suitable for mobile devices.14. Patch Antenna: A type of antenna that consists of a flat, rectangular sheet of metal mounted on a dielectric substrate. Patch antennas are commonly used in mobile devices for their compact size and ability to support various polarizations, including circular polarization.15. Proximity Sensor: A sensor that detects the presence of nearby obj ects without physical contact. In mobile handsets, proximity sensors can be used to adjust the radiation pattern of the antenna based on the user's position.16. Accelerometer Sensor: A sensor that measures acceleration forces. In mobile handsets, accelerometers can be used to detect the orientation of the device and adjust the antenna's radiation pattern accordingly.17. High Dielectric Constant: A property of a material that indicates its ability to store electrical energy in an electric field. Materials with a high dielectric constant are used in antennas to reduce size and enhance performance.18. Substrate: The base material upon which the components of an antenna, such as conductive traces and AMC structures, are fabricated. The choice of substrate material affects the antenna's performance, including size, gain, and SAR.19. Unit Cell: The smallest repeating structure in a metamaterial or meta surface. In the context of AMCs and EBG structures, unit cells are designed to manipulate electromagnetic waves in specific ways to achieve desired antenna performance.20. Zero Phase Reversal: A property of surfaces, such as AMCs, where the reflected wave does not undergo a phase shift, ensuring that the reflected signal does not interfere destructively with the radiated field.

[0004] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers, material percentages or ratios, reaction conditions, and other numerical values are also to be understood as modified by the term "about" in all cases.

[0005] It is also to be understood that the word “about”, “about” or “approximately” means an acceptable error for a particular value as determined by one of ordinary skill in the art, which depends in part on how the value is measured or determined. Insofar as it refers to percentages in the specification and claims, it means rounding up or down to the nearest whole number percentage. Insofar as it refers to other numbers in the specification and claims, it means plus or minus 10%.

[0006] Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending on the desired properties sought to be obtained. Without attempting to limit the application of the doctrine of equivalents to the claims, at a minimum each numerical parameter should be interpreted in light of the reported number of significant figures and by applying normal rounding techniques.

[0007] The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and / or the specification may mean “one”, but it is also consistent with the meaning of “one or more”, “at least one”, and “one or more than one”. Similarly, the word “another” may mean at least a second or more.

[0008] As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as "comprise1and "comprises”), “having” (and any form of having, such as “have and “has”), “including” (and any form of including, such as “include and “includes”) or “containing” (and any form of containing, such as “contain” and “contains”), are inclusive or open-ended and do not exclude additional, unrecited elements.BACKGROUND OF THE INVENTION

[0009] A satellite-compatible handset antenna must fulfill three key design criteria. Firstly, it requires sufficient gain to communicate effectively with the satellite and meet the necessary link budget specifications. Secondly, it must adhere to regulatory SAR standards to minimize the radio frequency (RF) energy absorbed by the human body, a concern thatintensifies at higher power levels. Lastly, the antenna design must fit within the physical constraints of a contemporary mobile handset.

[0010] While conductive surfaces used as reflectors can enhance antenna gain, they alter the phase of the reflected wave and affect the propagation of surface waves. This necessitates placement at the precise quarter-wavelength distance, complicating their integration into the limited space of a mobile handset.

[0011] Frequency Selective Surfaces (FSS) are a general term for periodic surfaces that exhibit reflective or transmissive properties based on the frequency of the incident electromagnetic waves. FSS can be used in antenna systems to filter specific frequencies, improving overall performance. This technology is pertinent to mobile handset antennas where space constraints necessitate compact and efficient designs.SUMMARY OF THE INVENTION

[0012] It is possible to change a conductor's surface properties by applying a unique texture to it. This textured metalized surface conducts DC currents, but over certain frequencies, limits conduction of AC currents. This changes the surface into one with high electromagnetic impedance, which does not alter the phase of reflected waves even if placed very close to the antenna. Additionally, the image currents appear in-phase instead of out-of-phase as with regular conductors.

[0013] High Impedance Surfaces (HIS) are a class of metamaterials engineered to have high surface impedance over a certain frequency range. HIS structures prevent surface wave propagation and can be designed to reflect electromagnetic waves without phase reversal. This invention makes HIS a valuable component in its antenna design, particularly for mobile handsets where space is at a premium and performance must be maximized.

[0014] HIS are also known as Artificial Magnetic Conductors (AMCs) and have been underutilized in the realm of mobile handset terminals intended for satellite communication, where EIRP requirements are substantially more stringent. Near-field radiation at higher power emanating from a handset antenna has significant implications on SAR, particularly when the handset is placed next to the human head.

[0015] HIS-EBG (Electromagnetic Band Gap) structures are periodic arrangements that prohibit the propagation of electromagnetic waves within a certain frequency range, creating a band gap. This invention utilizes EBGs in its antenna design to suppress unwanted surface waves, reduce mutual coupling between antenna elements, and improve overall radiation performance. Incorporating EBG structures into mobile handsets can significantly enhance antenna efficiency and reduce SAR.

[0016] Unlike standard conductors, the AMC’s textured surface reduces the propagation of surface waves, effectively constructing a grounding plane for innovative low-profile antennas and other radiating structures. It has been found that a variety of practical handset antennas including planar (such as patch or inverted-F) and helical type structures incorporating multiple AMC “cells” can help reduce SAR and boost gain, resulting in an increase of EIRP in the communication link between the handheld device and the satellite. AMCs are therefore preferable in optimising the directivity and efficiency of the handheld device.

[0017] Furthermore, the incorporation of AMCs can also add dynamic beam steering or multi-beaming capabilities. The approach also supports the implementation of multiple antennas on one user terminal, allowing beams to be formed for different user modes, such as steering the beam towards the satellite in the handheld “talk” position or in a standalone “fixed” position. The beam steering feature significantly enhances gain and ensures a more focused and robust link with the satellite for different user applications. The use of two or more antenna elements further facilitates SAR reduction as RF forward power is distributed between antenna ports.

[0018] The invention can further improve mobile handset antennas by enabling time division duplex (TDD) operation, where HIS elements are dynamically tuned to serve as both transmit and receive antennas at different frequencies. Controlled by the handset's internal signals, the HIS elements switch between the transmit frequency (fl) and receivefrequency (f2), by enabling the proximate placement of the distinct antennas while suppressing interference.

[0019] The amalgamation of these technologies in the antenna design of the invention contributes to a substantially more efficient and reliable communication system from the handset to the satellite in space.

[0020] In an embodiment, this invention uses multiple cross shaped AMC cells placed around a dual patch (planar) antenna designed for a mobile handset for a specific satellite communication application. The patch antennas employ circular polarization which matches the antenna technology used on the satellite network. The patch and AMC design is employed on a high dielectric constant (typical DK > 10), low loss printed circuit board (PCB) material which enables size reduction on the handset.

[0021] The design parameters including the thickness of the substrate are all intended to reduce surface waves with the substrate able to absorb near-field radiation, thus contributing to decreased SAR.

[0022] Distinctively, unlike metallic ground planes, the AMC structure of the invention does not compromise the antenna’s performance. This is ascribable to the certain characteristics of the AMCs, which include zero phase reversal and the suppression of surface wave propagation. These unique traits facilitate an elevation in the gain of the antenna, which sequentially leads to an enhancement in EIRP. Simultaneously, there is a considerable reduction in SAR. Therefore, the integration of an AMC presents a formidable innovation for optimizing performance in mobile handset terminals used in satellite communication.

[0023] A summary of the main aspects of the invention is as follows:

[0024] In one embodiment, the invention relates to a mobile handset antenna system for satellite communication that incorporates a high dielectric constant substrate supporting an antenna array. This system integrates an artificial magnetic conductor (AMC) surface, which is adapted to enhance the gain of the antenna system while simultaneously reducing the Specific Absorption Rate (SAR). The antenna array is configured with multiple antennaelements capable of beam steering, allowing the system to adjust its radiation pattern based on the operational mode of the mobile handset.

[0025] In a further embodiment, the AMC surface comprises multiple unit cells that suppress surface waves by creating a high impedance structure, where tangential magnetic fields are minimized. This configuration produces a zero-phase reflection surface when positioned close to the antenna, which further increases the antenna's gain and reduces SAR. The antenna system also includes a patch antenna configured to support circular polarization, matching the polarization requirements of satellite communication systems.

[0026] Additionally, the antenna system may include multi-patch antennas and the AMC surface mounted on a printed circuit board (PCB) with a high dielectric constant and low loss properties. The system's beam steering capabilities are dynamic, with at least one beam steering element directing the radiation pattern towards a satellite in communication. This beam steering is facilitated by utilizing proximity and accelerometer data from the mobile handset, enabling efficient communication with satellites.

[0027] Further embodiments of the invention include configurations where the AMC structure supports dynamic beam steering or multi-beaming capabilities, potentially using pin diodes to control the AMC surface. A helical antenna may also be integrated with the AMC structure to further enhance the antenna system's performance. Moreover, the antenna array is designed to provide multi-beam capabilities, enabling various communication modes between the handset and the satellite.

[0028] The invention also describes methods for improving mobile handset communication with satellites, such as employing a high dielectric constant substrate with an antenna array and integrating an AMC surface to reduce SAR and enhance gain. These methods may involve steering multiple beams from the antenna array towards a satellite based on the user's position, configuring beam directionality for different user modes, and employing a planar inverted-F antenna (PIFA) in combination with the AMC structure to improve gain and reduce SAR. Furthermore, the AMC surface can be configured to suppress surface wave propagation without inducing phase reversal upon reflection, thereby optimizing the system's directivity and efficiency.

[0029] This marks the pioneering implementation of a multi-antenna system integrated with an artificial magnetic conductor in a mobile handset. This compact antenna solution has been devised for satellite communications, introducing a novel blend of SAR mitigation and gain enhancement within a constrained form-factor. Most significantly, it features a control system to regulate beam directionality skywards, thereby revolutionizing the concept of portable handset terminal antenna solution for satellite communication systems. It allows the beam pattern to be steered according to the use-case, whether held to the head or held in the hand. Adaptive beam steering in the handset can be based on proximity and accelerometer sensors available inside the mobile handset.

[0030] Other and further aspects and advantages of the present invention will be obvious upon an understanding of the illustrative embodiments about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and other aspects, features and advantages of the invention will become more readily apparent from the following description, reference being made to the accompanying drawings in which:

[0032] Figure 1 is a schematic embodiment an AMC surface used on a smart mobile handset with expected gap below a length L in accordance with the invention.

[0033] Figure 2 shows a perspective view of an AMC unit cell example which could be exploited for integration into mobile handset in accordance with the invention.

[0034] Figure 3 shows a perspective view of an AMC unit cell example which could be exploited for integration into mobile handset in accordance with the invention.

[0035] Figure 4 shows a perspective view of an AMC unit cell example which could be exploited for integration into mobile handset in accordance with the invention.

[0036] Figure 5 shows a perspective view of an AMC unit cell example which could be exploited for integration into mobile handset in accordance with the invention.

[0037] Figure 6 is a schematic embodiment of an AMC structure integrated with a quadrifilar helix antenna in accordance with the invention.

[0038] Figure 7 is a schematic embodiment of an AMC structure integrated with a Planar Inverted-F Antenna (PIFA) in accordance with the invention.

[0039] Figure 8 is a schematic embodiment of an AMC structure integrated with a circular polarization patch antenna in accordance with the invention.

[0040] Figure 9 is a schematical representation of an embodiment of an AMC integrated patch antenna on the same metalized surface in accordance with the invention.

[0041] Figure 10 is a schematical representation of an example a pair of patch antennas with AMC integrated in the back cover of a portable phone assembly in accordance with the invention.DETAILED DESCRIPTION OF THE INVENTION

[0042] In the following description, similar features in the drawings have been given similar reference numerals, and in order not to weigh down the figures, some elements are not referred to in some figures if they were already identified in another figure.

[0043] The invention leverages two primary components to achieve SAR reduction and improve antenna performance: a suitable antenna on a dielectric substrate and an artificial magnetic conductor.

[0044] Meta surfaces are two-dimensional analogs of metamaterials consisting of periodic or quasi-periodic arrangements of subwavelength elements. These structures can manipulate electromagnetic waves in unconventional ways, such as altering the phase, amplitude, or polarization. In the context of mobile handset antennas, meta surfaces can be engineered to enhance radiation patterns, suppress surface waves, and contribute to SAR reduction.

[0045] Referring to Figure 1, a schematic embodiment of an AMC surface 100 is shown used on a smart mobile handset 102. The AMC surface 100 comprises an expected gap below a length L of about, for example, 5mm in accordance with the invention. A human head 104 is shown to indicate the proximity to the handset. The mobile handset 102 isequipped with and antenna 106 and a group plane 108. The AMC surface 100 is depicted with a detailed pattern 110 of unit cells designed to optimize antenna performance.1. Antenna arrays on substrate:

[0046] In an embodiment, a dual or quad patch circular polarization antenna is employed. Circular polarization is typically helpful in satellite communications. The antenna is based on a high dielectric constant, low loss substrate facilitating a reduction in size due to the wavelength reduction in the substrate material. The dielectric is an insulating material that can be polarized by an applied electric field. When a dielectric is exposed to an electromagnetic field, it can store and dissipate the energy of the field, mitigating the near- field radiation that would otherwise contribute to a higher SAR. Thus, the use of a substrate effectively helps absorbs a portion of this near-field radiation and reduces the amount of energy that might be absorbed by the human body.

[0047] Referring now to Figures 2-5, examples of AMC unit cells 200 are shown. AMC unit cells 200 may be integrated into mobile handsets in accordance with the invention. Each unit cell 200 consists of a shaped copper top layer 202, a substrate 204, and a ground bottom layer 206. Various shapes, such as crosses and squares, are demonstrated to illustrate the versatility of the AMC design.

[0048] Metamaterials are artificially structured materials engineered to have properties not found in naturally occurring materials. These materials can control electromagnetic waves in novel ways, such as negative refraction or cloaking. By integrating metamaterials into novel mobile handset antennas, it is possible to achieve superior performance characteristics, such as increased gain and reduced SAR, which are crucial for efficient satellite communication.

[0049] Referring now to Figure 6-8, a schematic embodiment of AMC structures integrated with different antenna solutions such as a quadrifilar helix antenna 300, a Planar Inverted-F Antenna (PIFA) 302, and a circular polarization patch antenna 304. The AMCstructures 306 are shown enhancing the performance of each antenna type by reducing SAR and improving gain.

[0050] Additionally, the use of two or more antennas, allows the array beam to be directed for different use cases. For example, in the typical handheld case, the beam would be directed skywards. Crucially, the use of two or more antennas also helps to further reduce SAR since RF energy can be distributed between multiple antennas instead of being concentrated in one antenna port.

[0051] The invention leverages the use of diodes, such as PIN diodes or varactor diodes, integrated into the AMC surface to enable dynamic tuning of its operational frequency. By selectively biasing these diodes, the electrical length and impedance properties of the AMC surface can be altered, allowing it to suppress surface waves at different frequencies. In the case of TDD operation, the diodes can be switched on and off in synchronization with the handset's internal control signals, thereby adjusting the AMC surface to function optimally at the transmit frequency (fl) during transmission and the receive frequency (f2) during reception. This dynamic tuning capability allows for efficient use of the same AMC elements for both transmitting and receiving functions,

[0052] Referring now to Figure 9, an AMC integrated patch antenna 400 is shown. The AMC integrated patch antenna 400 is presented on a metalized surface in accordance with the invention. The patch antenna 402 is surrounded by AMC unit cells 404, which help in controlling the radiation pattern and reducing SAR. The integrated design ensures a compact and efficient solution for mobile handset antennas.2. Artificial Magnetic Conductor (AMC):

[0053] Implementing an artificial magnetic conductor beneath or near the antenna, further reduces SAR. Like a metallic ground plane, an artificial magnetic conductor reflects the radiated field away from the head. These characteristics make them a more effective choice for this application.

[0054] Referring now to Figure 10, a pair of patch antennas 500 with AMC integrated into the back cover of a portable phone assembly 502 is shown. The receive antenna 504 andtransmit antennas 506 are shown, with the AMC surface 508 providing improved performance by minimizing SAR and enhancing gain.

[0055] Unlike conventional metallic ground planes, which often suffer from unwanted surface wave propagation and phase reversal issues, an artificial magnetic surface suppresses surface waves and does not induce a phase reversal upon reflection. Surface wave suppression is vital because surface waves can lead to energy losses, distort the antenna's radiation pattern, and even cause interference with other devices. The absence of phase reversal means the reflected wave from the surface will not destructively interfere with the antenna's radiated field. This ensures a more effective and predictable radiation pattern.

[0056] These unique properties of artificial magnetic conductors allow for an increase in the gain of the antenna, essentially enhancing the strength of the signal it can send or receive. This increased gain sequentially improves the EIRP, a measure of the total power that a theoretical isotropic antenna (which distributes power equally in all directions) would emit to produce the peak power density observed in the direction of maximum antenna gain.

[0057] Overall, integrating an antenna (array) with a dielectric substrate with AMC presents a significant innovation in mobile handset design. This combination not only optimizes performance for satellite communications by increasing antenna gain and EIRP but also ensures safety by reducing the SAR, making mobile handsets safer for users.

[0058] While illustrative and presently preferred embodiment(s) of the invention have been described in detail hereinabove, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art. It is also to be understood that the phraseology or terminology used herein is for the purpose of description and not limitation.

Claims

CLAIMS1. A mobile handset antenna system for satellite communication, comprising: an antenna array mounted on a high dielectric constant substrate; an artificial magnetic conductor (AMC) surface integrated with said substrate adapted to enhance gain and reduce Specific Absorption Rate (SAR).

2. The system of claim 1, wherein the antenna array includes multiple antenna elements using beam steering to adjust the radiation pattern based on the operational mode of the mobile handset.

3. The system of claim 1, wherein the AMC comprises multiple unit cells working to suppress surface waves by creating a high impedance structure where tangential magnetic fields are minimised and a zero-phase reflection surface is created when placed closed to the antenna, increasing gain and reducing SAR.

4. The system of claim 1, wherein a patch antenna is configured to support circular polarization matching the polarization of a satellite communication system.

5. The system of claim 1, wherein the multi-patch antenna and the AMC surface are mounted on a printed circuit board (PCB) with a high dielectric constant and low loss properties.

6. The system of claim 2, wherein the at least one of said beam steering elements is capable of dynamically directing the radiation pattern towards a satellite in communication.

7. The system of claim 2, wherein the beam steering is achieved by utilizing proximity and accelerometer data from the mobile handset.

8. The system of claim 2, wherein the antenna is configured to reduce SAR by distributing RF forward power between the multiple antenna ports.

9. The system of claim 1, wherein the AMC structure can support dynamic beam steering or multi-beaming capabilities, for example using pin diodes to control the AMC surface.

10. The system of claim 1, further comprising a helical antenna integrated with the AMC structure.

11. The system of claim 1, wherein the antenna array comprises multi -beam capabilities to allow different communication modes between the handset and the satellite.

12. A method for improving a mobile handset communication with satellites, the method comprising: employing a high dielectric constant substrate with an antenna array in the handset; integrating an AMC surface in the handset adapted to reduce SAR and enhance gain.

13. The method of claim 12, further including steering multiple beams from the antenna array towards a satellite based on the user's position.

14. The method of claim 12, wherein the AMC surface effectively suppresses surface wave propagation and does not induce phase reversal upon reflection.

15. The method of claim 12, further comprising selecting antenna elements based on their ability to integrate with AMC surfaces; and configuring the AMC surfaces to optimize directivity and efficiency for enhanced EIRP.

16. The method of claim 12, wherein the method includes configuring the beam directionality for different user modes, such as the handheld “talk” position or a standalone “fixed” position.

17. The method of claim 12, wherein the AMC surface comprises a textured metalized surface adapted to modify the electromagnetic surface impedance.

18. The method of claim 12, further comprising employing a planar inverted-F antenna (PIFA) in combination with the AMC structure adapted to improve gain and reduce SAR.

19. The method of claim 12, wherein the antenna array includes a multiple patch antenna array employing circular polarization.

20. The method of claim 12, further comprising employing a substrate with low loss properties adapted to reduce the antenna size due to wavelength reduction in the substrate material.

21. The method of claim 12, including the use of an artificial magnetic conductor beneath or near the antenna to reflect radiated fields away from the user, enhancing safety and antenna performance.

22. A method for improving a mobile handset communication with satellites, the method comprising: employing a high dielectric constant substrate with multiple antennas operating at different frequencies; integrating a diode tunable AMC surface in the handset adapted to reduce SAR and enhance gain.

23. The system of claim 22, wherein the HIS type material is configured to be tuneable to different frequencies, allowing shared use of the same HIS elements for both transmit and receive antennas, controlled by timing signals provided by the mobile handset for time division duplex (TDD) operation.

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