WO2016069014A1

WO2016069014A1 - Dielectric resonator antenna

Info

Publication number: WO2016069014A1
Application number: PCT/US2014/063533
Authority: WO
Inventors: Mai O. SALLAM; Ezzeldin Soliman; Mohamed SERRY; Sherif Sedky
Original assignee: The American University In Cairo
Priority date: 2014-10-31
Filing date: 2014-10-31
Publication date: 2016-05-06

Abstract

A dielectric resonator antenna is provided that includes a silicon cylinder, a silicon substrate, where the silicon cylinder is disposed on the silicon substrate, a magnetic dipole, where the magnetic dipole is disposed on a bottom side of the silicon substrate, and a coplanar waveguide, where the coplanar waveguide is disposed on the bottom side of the silicon substrate, where the magnetic dipole terminates the coplanar waveguide feeding line. A circular cusp layer having an off-center circular cutout with a circular copper layer therein provides linear polarization and circular polarization capabilities according to the orientation of the magnetic dipole, circular cutout and copper layer relative to the silicon cylinder when viewed from the top.

Description

DIELECTRIC RESONATOR ANTENNA

FIELD OF THE INVENTION

The invention relates generally to dielectric resonator antennas. More particularly the invention relates to micromachined on-chip dielectric resonator antennas.

BACKGROUND OF THE INVENTION

The ever-increasing demand for high performance communication systems has motivated the shift of wireless systems towards the millimeter-wave (mm-wave) range. At these relatively high frequencies, microstrip antennas suffer from high conductor and substrate losses resulting in the deterioration of the antenna radiation efficiency. The replacement of the lossy planar metallic antennas with high permittivity Dielectric Resonator Antennas (DRAs) is considered a good solution to this problem. Since the idea of using Dielectric Resonators (DRs) as radiating antennas was first introduced, DRAs received great attention due to their appealing characteristics like small footprint, light weight, absence of surface wave and metallic losses. In addition, DRAs can have various geometrical topologies. DRAs can be excited using a variety of feeding structures like co-axial lines, microstrip lines, coplanar waveguides, aperture excitation, and even conformal strip excitation. However, the fabrication of DRAs in the millimeter-wave range is challenging, owing to the relatively small features required. The thickness of the substrate carrying the feeding microwave circuit must be electrically thin in order to avoid multiple surface wave modes excitation. Besides, any misalignment between the DRA and the feeding structure results in significant impedance mismatch. Research carried out in the area of DRAs can be classified into two categories. The first category is concerned with improving the antenna electrical characteristics. The substrates carrying the driving circuit are made from non-semiconductor materials (neither silicon nor GaAs). Therefore, antennas in this category are not suitable for on-chip integration. In one instance, the substrate used has relative permittivity, ε_Γ, of 10.2, whereas in another instance, the substrates used are teflon with ε_Γ = 2.2. In a further instance, stacked DRAs are designed to achieve good radiation characteristics where a gain of 6 dBi and bandwidth of 24% are realized. Another technique for improving the gain was introduced included enhancing the gain of the DRA by using a superstrate located at a certain distance from the DRA. A gain higher than 1 1 dBi and a bandwidth of 18.4% were obtained. Further enhancement for the gain was made, where the superstrate is stacked with multiple metallic strips. The gain of that antenna is higher than 15.4 dBi over its working bandwidth. Excitation of higher order modes of the DRA is also considered a method for improving the gain. In one attempt, the higher order modes of the TE_n3 mode (TE_U5 , and TE_U9) are excited in; whereas the modes HE_l5S and ΗΕ_ηδ are excited in other attempts.

The second category of DRAs uses either silicon or GaAs substrate that can carry the driving electronics. In one case, a DRA is fed by a coplanar waveguide (CPW) to excite the ΗΕ _δ mode. The proposed antenna in that work had a gain of 3.2 dBi. However, it suffers from low radiation efficiency (51%). In another attempt, the DRA is fed by a H-slot which excites the TE mode. This antenna has an improved radiation efficiency of 59% while its measured gain is 0.5 dBi. At one time, a Dielectric Resonator Antenna above Patch (DRAP) is introduced. The substrate of the antenna was GaAs. This antenna had a good impedance bandwidth (29.2%), whereas it had a gain of 3.6 dBi. For all these designs, the DRA itself is constructed from a material different from the silicon or GaAs substrate material, which requires hybrid integration. In one case, a high resistivity (p_si = 300 Ω ιη) silicon was used as a material for both the substrate and the four DRAs arranged as 2x2 array. A number of BenzoCycloButhene (BCB) films were deposited on top of the slotted ground plane at the back-side of the substrate to realize the feeding microstrip network. The gain of this DRA array was about 11 dBi and its simulated radiation efficiency is 62%. Such antenna represented a complete on-chip solution in which the DRA is micromachined within the same wafer carrying the driving circuit.

What is needed is a simplified on-chip DRA that eliminates a need for a microstrip network and BCB layers on a single wafer.

SUMMARY OF THE INVENTION

To address the needs in the art, a dielectric resonator antenna is provided that includes a silicon cylinder, a silicon substrate, where the silicon cylinder is disposed on the silicon substrate, a magnetic dipole, where the magnetic dipole is disposed on a bottom side of the silicon substrate, and a coplanar waveguide, where the coplanar waveguide is disposed on the bottom side of the silicon substrate, where the magnetic dipole terminates the coplanar waveguide feeding line. According to one aspect of the invention, the magnetic dipole is disposed proximal to an edge of the silicon cylinder and within the silicon cylinder when viewed from the top.

In another aspect the invention further includes a copper circular patch layer disposed on top of the silicon cylinder, where a diameter of the copper circular patch layer is smaller than a diameter of the silicon cylinder. In yet another aspect the invention further includes a circular copper cusp layer disposed on the silicon cylinder, where the circular copper cusp layer has an outer diameter that is proximal to the diameter of the silicon cylinder where the cusp includes an off-center circular cutout therein, where the off-center circular cutout has a diameter that is smaller than the circular copper cusp layer outer diameter, where the off-center circular cutout includes a copper circular layer disposed therein, where the copper circular layer has a diameter that is smaller than the off-center circular cutout diameter. According to one aspect of the current embodiment, the circular copper cusp layer is positioned proximal a six o'clock position when viewed from the top, where the off-center circular cutout is positioned proximal to the six o'clock position when viewed from the top, where the off- center circular cutout is positioned symmetric to the feeding line, where the magnetic dipole along the substrate bottom is disposed proximal to a center of the silicon cylinder and proximal to an edge of the circular cutout when viewed from the top, where the dielectric resonator antenna is capable of linear polarization. According to one aspect of the current embodiment, the circular copper cusp layer is positioned proximal a twelve o'clock position when viewed from the top, where the off-center circular cutout is positioned proximal to the twelve o'clock position when viewed from the top, where the off-center circular cutout is positioned symmetric to the feeding line, where the magnetic dipole along the substrate bottom is disposed proximal to the six o'clock position of the silicon cylinder, and proximal to the edge of the off-center cutout, where the feeding lines are directed along the six o'clock position along the substrate bottom when viewed from the top, where the dielectric resonator antenna is capable of linear polarization. According to another aspect of the current embodiment, the circular copper cusp layer is positioned proximal a three o'clock position when viewed from the top, where the off-center circular cutout is positioned proximal to the three o'clock position when viewed from the top, where the magnetic dipole is disposed proximal to a center of the silicon cylinder and the feeding lines are directed along the six o'clock position along the substrate bottom, where the dielectric resonator antenna is capable of circular polarization. In yet another aspect of the current embodiment, the circular copper cusp layer is positioned proximal a center location between a one o'clock position and a two o'clock position when viewed from the top, where the off-center circular cutout is positioned between a one o'clock position and a two o'clock position two o'clock position when viewed from the top, where the off-center circular cutout is positioned at an angle to the magnetic dipole, where the magnetic dipole along the substrate bottom is disposed proximal to the six o'clock position of the silicon cylinder, where the feeding lines are directed along the six o'clock position along the substrate bottom when viewed from the top, where the dielectric resonator antenna is capable of circular polarization.

According to one embodiment of the invention, the circular copper cusp layer is positioned proximal a nine o'clock position when viewed from the top, where the off-center circular cutout is positioned proximal to the nine o'clock position when viewed from the top, where the magnetic dipole is disposed proximal to a center of the silicon cylinder and the feeding lines are directed along the six o'clock position along the substrate bottom when viewed from the top, where the dielectric resonator antenna is capable of circular polarization.

In yet another embodiment of the invention, the circular copper cusp layer is positioned proximal a center location between a ten o'clock position and an eleven o'clock position when viewed from the top, where the off-center circular cutout is positioned proximal between the ten o'clock position and the eleven o'clock position when viewed from the top, where the off-center circular cutout is positioned at an angle to the magnetic dipole when viewed from the top, where the magnetic dipole is disposed proximal to a six o'clock position of the silicon cylinder, where the feeding lines are directed along the six o'clock position along the substrate bottom when viewed from the top, where the dielectric resonator antenna is capable of circular polarization.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGs. la-lc show (la) front view, (lb) back view, and (lc) an oblique view of the DRA, according to one embodiment of the invention.

FIGs. 2a-2c show (2a) front view, (2b) back view, and (2c) an oblique view of a DRA assembly having a patch layer disposed on the top surface of the silicon cylinder, according to one embodiment of the current invention.

FIGs. 3a-3c show (3a) front view, (3b) back view, and (3c) an oblique view of a DRA assembly having a cusp layer and that is capable of linear polarization operation, according to one embodiment of the current invention.

FIG. 4 shows a schematic view of the DRA described in FIGs. 3a-3c, according to one embodiment of the current invention.

FIGs. 5a-5c show (5a) front view, (5b) back view, and (5c) an oblique view of a DRA assembly that is capable of linear polarization operation, according to one embodiment of the current invention.

FIGs. 6a-6d show (6a) front view, (6b) back view, (6c) an oblique view, and (6d)

mirrored planar view of the configuration shown in (6a) of a DRA assembly that is capable of circular polarization operation, according to one embodiment of the current invention. FIGs. 7a-7d show (7a) front view, (7b) back view, (7c) an oblique view, and (7d) mirrored planar view of the configuration shown in (7a) of a DRA assembly that is capable of circular polarization operation, according to one embodiment of the current invention.

DETAILED DESCRIPTION

The current invention provides a cylindrical DRA suitable for on-chip applications. According to one embodiment, the DRA is micromachined in silicon. A Coplanar Waveguide (CPW) structure is used to feed the DRA, instead of the microstrip network used in the current art. Therefore, no BCB layers are required, which leads to a simpler and less expensive design. Unlike the CPW-fed DRAs currently in the art, the CPW feeding line of one embodiment of the current invention is placed at the underside of the substrate. This facilitates the construction of the DRA and its feeding network using a single wafer. The structure of one embodiment of the current invention is shown in FIGs. la-lc, where shown is a cylindrical DRA 100 that includes a silicon substrate 102, a silicon cylinder 104, disposed on the silicon substrate 102, a magnetic dipole 106 disposed on a bottom side of the silicon substrate 102, and a CWP feeding line 108 disposed on the bottom side of the silicon substrate 102, where the magnetic dipole terminates the CPW feeding line 108. In one embodiment, the cylindrical DRA, with radius R is defined in a high resistivity silicon wafer by etching the silicon around the cylinder. The resistivity of the silicon wafer is 2,000Ωχιη, its dielectric loss tangent (tan δ) = 0.003, and its relative permittivity ε_Γ = 11.9. The wafers under consideration are 675 μιη thick. The height of the DRA in this exemplary embodiment is 400 μιη, whereas the remaining thickness for the substrate is 275 μιη. Such relatively thin substrate prevents the excitation of all surface wave modes except for the fundamental TMo mode. The DRA 100 is excited by a magnetic dipole with length L and width W. This dipole 106 terminates the CPW feeding line 108, whose slot width and slots separation are 40 and 68 μιη, respectively. The line's 108 dimensions correspond to a characteristic impedance of 50 Ω. The CPW feeding line structure 108 is located at the backside of the silicon wafer 102 (see FIG. lb), and the lateral spacing between the center of the feeding line 108 and that of the DRA cylinder 104 is denoted by S, as shown in FIG. lb.

The CPW feeding line 108 is excited with its odd mode where the magnetic currents flow in the two slots of the CPW feeding line 108 in opposite directions. This forces the magnetic currents to flow through the arms of the magnetic dipole 106 in the same direction. The magnetic field distribution on the top surface of the DRA cylinder 104 designed at 60 GHz was calculated by HFSS using finite element method and showed the field distribution matches that of the HE_US mode of the DRA. Here, the magnetic field along the DRA cylinder 104 has the same direction as the magnetic current flowing through the feeding magnetic dipole 106, and the maximum magnetic field along the plane perpendicular to the substrate and parallel to the magnetic dipole occurred at the interface between the DRA cylinder 104 and the substrate 102. This ensures maximum coupling from the CPW feeding line 108 to the desired DRA mode. In this exemplary embodiment, the coupling magnetic dipole 106 is not located at the center of the DRA 100 in order to achieve best matching with the CPW feeding line 108.

Regarding the effect of varying the geometrical design parameters of the DRA: R, L, W, and S on its frequency response (see FIGs. la-lc), TABLE I shows the sensitivity of the resonance frequency and return loss of the DRA 100 to 10% perturbation (increase) of its design parameters around their optimum values. The optimum values are listed in TABLE II. From TABLE I, it can be observed that the most effective parameter to tune the resonance frequency is the radius of the DRA cylinder 104, R. This was expected as the DRA cylinder 104 is the radiating element whose size must control most the value of the resonance frequency. The HFSS calculated return loss of the DRA versus frequency for different values of the DRA cylinder 104 radius, R was done, and it was found that as R increases the value of the resonance frequency decreases, while good matching is maintained. According to TABLE I, the length, L, and location, S, of the feeding dipole 106 play the major role in achieving good matching between the DRA radiating mode and the CPW feeding line 108. In other words, the input impedance of the DRA cylinder 104 is mostly controlled via the two parameters L and S.

TABLE I

SENSITIVITY OF THE RESONANCE FREQUENCY AND RETURN LOSS TO THE PERTURBATION

OF THE DRA DESIGN PARAMETERS

Resonance

Return Loss

Frequency

Antenna Sensitivity

Sensitivity

Parameter (dB/10%

(GHz/10%

Perturbation)

R -3.29 6.95

L -0.59 12.29

W -0.18 3.49

s 0.56 14.49

TABLE II

OPTIMUM DIMENSIONS OF THE DRA

Antenna Optimum Antenna Optimum

Parameter Value Parameter Value

L 1.068 mm W 265 μιη

R 1.18 mm S 1.2 mm

The variation of the input impedance of the DRA 100 was calculated using HFSS at 60 GHz versus L and S. As L increases, the real part of the input impedance decreases significantly. Unlike the resistive part of the input impedance, which is affected mainly by L, its imaginary part is affected by both L and S. As L increases, the antenna input impedance becomes more inductive due to the increased spacing between the short-circuit termination of the magnetic dipole and the feeding point. On the other hand, as S increases the DRA becomes more capacitive due to the increase in the equivalent modal voltage as one move away from the center of the DRA. According to one aspect, the region of maximum current, i.e. magnetic field, corresponds to minimum voltage, i.e. electric field, and vice versa. The structure of the current invention can be fabricated using micromachining technology in three steps, according to one embodiment. Six inch double sided polished high- resistivity silicon wafers (p_si > 2,000 Ωχιη and thickness = 675 μιη) were used for fabrication. One side of this wafer was etched through a depth of 400 μιη using a Deep Reactive Ion Etching (DRIE) process in order to remove the silicon around the DRA while maintaining vertical cylindrical sidewall, where a number of DRAs can be fabricated within the same wafer. Ideally, the silicon has to be removed totally in between adjacent DRAs. However, this process requires etching of huge amount of silicon. For fabrication simplicity, sufficient amount of silicon was etched away around the DRA, such that a minimum distance of 4 mm is kept clear in all directions. This leaves silicon walls surrounding the DRAs. The presence of these walls has a minor effect on the antenna's characteristics. The unetched bottom side of the wafer acts as the substrate for the antenna's feeding network. The backside was coated with a copper film having a thickness > 5 μιη using an electroplating process. Then, the backside Cu has been patterned using dry etching to define the feeding network.

The measured electrical characteristics of the fabricated DRA 100 were compared with calculated results. For accurate comparison, the silicon walls surrounding the DRA cylinder 104 were taken into consideration in the simulation. The simulations of the optimized DRA 100 were carried out using both HFSS and CST Microwave Studio (frequency domain solver). The three return loss curves showed good agreement. The measured resonance frequency was 59 GHz, exactly as determined by CST. The value determined by HFSS is 59.5 GHz, which was very close to the measured one. Measurements show better matching and slightly wider bandwidth than simulations. This is mainly due to extra losses that are not considered by the simulators. The measured -10 dB impedance bandwidth is 2.23 GHz, which corresponds to 3.78% at 59 GHz. Such bandwidth is considered sufficient for a number of mm-wave wireless systems. For WPAN applications where the bandwidth extends from 57 GHz to 64 GHz, two more designs of the proposed DRA are required to cover the whole band.

The 3D radiation pattern of the DRA, according to this exemplary embodiment, was calculated using HFSS and CST at their resonance frequencies. Very good agreement was observed. The antenna was radiating mainly towards the boresight. The calculated gain, directivity, and radiation efficiency are 8.27 dBi, 7.87 dBi, and 92.04%, respectively. The -15 dB back-side radiation is attributed mainly to radiation from the magnetic dipole etched within the ground plane.

Regarding measured and simulated co- and cross-polar components of the far field at the corresponding resonance frequency along the E- and H-planes, there was reasonable agreement between simulations and measurements, while the two simulators agree very well with each other. It is clear that the DRA 100 according to the current invention has a high degree of polarization purity especially in the broadside direction. The simulated and measured cross-polar levels in the broadside direction were -42.25 dB and -15.00 dB, respectively. The relatively higher measured cross-polarization level was mainly due to unwanted reflections within the measurement setup. The measured 3-dB beamwidth of the DRA 100 in this exemplary embodiment was 45° and 114° in the E- and H- planes, respectively. The maximum gain and radiation efficiency were plotted versus frequency, as simulated with HFSS and CST. At 60 GHz, the gain and radiation efficiency were 7.87 dBi and 92.04%, respectively, which clearly shows it to be almost constant over the whole working frequency bandwidth of the DRA 100.

Turning again to the figures, FIGs. la-lc show one embodiment of the DRA invention 100, that shows the silicon (Si) substrate 102 of thickness = 275 μιη, where the current embodiment is available for two versions of silicon wafers: high-resistivity (2000 ohm.cm), and low-resistivity (45 ohm.cm). Each type is suitable for certain application. The dimensions are optimized for each case. According to one embodiment, the DRA cylinder 104 has a height = 400 μιη, and radius = 1.18mm (high-resistivity) and radius = 1.1mm (low-resistivity). The CPW feeding line 108 is copper deposited on the bottom side of silicon substrate 102, where the CPW feeding line 108 has a slot width = 40 μιη, and the distance between slots = 68 μιη that is ended by magnetic dipole 106 feeding the DRA cylinder 104. The dipole 106 has length (L) of 1.068 mm (high-resistivity), 1.208 mm (low-resistivity), and width (W) of 0.265 mm (high-resistivity), 0.25 mm (low resistivity). According to one aspect of the current embodiment, the distance (S) between the center of the dipole 106 and that of the DRA cylinder 104 center is 0.9 mm (high-resistivity), 1 mm (low-resistivity), when viewed from the top.

According to another embodiment of the current invention, FIGs. 2a-2c show a DRA assembly 100 having a patch layer 202 disposed on the top surface of the DRA cylinder 104. According to this exemplary embodiment, the silicon (Si) substrate 102 has a thickness = 275 μιη. The current embodiment can include two versions of silicon wafers: high-resistivity (2000 ohm.cm), and low-resistivity (45 ohm.cm). Each type is suitable for certain application. The dimensions are optimized for each exemplary case. Here, the Si DRA cylinder 104 has a height = 400 μιη, and radius = 1.11 mm (high-resistivity) and 1.15mm (low-resistivity). The current embodiment includes a circular copper patch 202 placed on top of the DRA cylinder 104. According to the current embodiment, the patch 202 has radius of 0.97 mm (high-resistivity) and 1.05 mm (low-resistivity). In a further aspect of the current embodiment, the CPW feeding line 108 comprising copper deposited on bottom side of silicon substrate 102 has a slot width = 40 μιη, and distance between the slots = 68 μιη that is ended bymagnetic dipole 106 feeding the DRA cylinder 104. The dipole 106 has length (L) of 1.268 mm (high-resistivity) and 1.268 mm (low-resistivity), and a width (W) of 0.32 mm (high-resistivity), 0.25 mm (low-resistivity). The distance (S) between the center of the feeding dipole 106 and that of the DRA cylinder 104 center is 0 mm (high-resistivity), 0 mm (low-resistivity), when viewed from the top.

FIGs. 3a-3c show a DRA assembly 100 having a cusp layer 302 that is capable of linear polarization operation. According to one embodiment, the silicon substrate 102 has a thickness = 275 μιη. The current embodiment is available for high-resistivity silicon wafer only. In one aspect, the DRA cylinder 104 has a height = 400 μιη, and a radius = 1.1 mm. According to the current embodiment, a circular copper cusp 302 is placed on top of the DRA cylinder 104, where the circular copper cusp layer 302 has an outer diameter that is proximal to the diameter of the silicon DRA cylinder 104. The cusp layer 302 includes an off-center circular cutout (or uncoated region of the silicon cylinder top surface) therein, where the off-center circular cutout has a diameter that is smaller than the circular copper cusp layer 302 outer diameter, where the off-center circular cutout includes a copper circular layer 304 disposed therein, where the copper circular layer 304 has a diameter that is smaller than the off-center circular cutout diameter so as to fit within the cutout. According to one aspect of the current embodiment, the circular copper cusp layer 302 is positioned proximal a six o'clock position when viewed from the top, where the off-center circular cutout and copper circular layer 304 are positioned proximal to the six o'clock position when viewed from the top, where the off-center circular cutout copper circular layer 304 is positioned symmetric to the feeding line 108, where the magnetic dipole 106 along the substrate bottom is disposed proximal to a center of the silicon cylinder 104 and proximal to an edge of the circular cutout and copper circular layer 304 when viewed from the top, where the dielectric resonator antenna 100 is capable of linear polarization. The distance (S) between the center of the feeding dipole 106 and that of the DRA cylinder 104 center is 0 mm (high-resistivity), when viewed from the top.

FIG. 4 shows a schematic drawing of one embodiment of the DRA assembly 100 having a cusp layer 302 that is capable of linear polarization operation, and provides reference labels for further embodiments described herein.

Returning now to FIG. 3, the DRA assembly 100 is shown with the dimensions of the cusp 302 i?cutout = 0.95 mm, Rin = 0.52 mm, SI = 0.05 mm , and S2 = 0.05 mm. According to this exemplary embodiment, the coplanar waveguide feeding line 108 has a slot width = 40 μιη, and a distance between slots = 68 μιη ended by magnetic dipole feeding the DRA cylinder 104. The dipole 106 has length (L) of 1.388 mm, and width (W) of 0.07 mm (see FIGs. la-lc and FIG. 4).

According to a further embodiment of the invention, FIGs. 5a-5c show a DRA assembly 100 having a cusp layer 302 that is capable of linear polarization operation. In this exemplary embodiment, the silicon substrate 102 has a thickness = 275 μιη. The current embodiment is available for high-resistivity silicon wafer only. The DRA cylinder 104 has a height = 400 μιη, and a radius = 1.16 mm. According to the current embodiment, the circular copper cusp 302 is placed on top of the DRA cylinder 104. The dimensions of the copper cusp is i?cutout = 0.91 mm, Rin =0.45 mm, SI = 0.08 mm, and S2 = 0.05 mm. According to this exemplary embodiment, the coplanar waveguide feeding line 108 has a slot width = 40 μιη, and a distance between slots = 68 μιη ended by magnetic dipole 106 feeding the DRA cylinder 104. The dipole 106 has length (L) of 1.618 mm, and width (W) of 0.12 mm (see FIGs. la-lc and FIG. 4). The distance between the center of the feeding dipole 106 and that of the DRA cylinder 106 center is 0.65 mm (high-resistivity). According to one aspect of the current embodiment, the circular copper cusp layer 302 is positioned proximal a twelve o'clock position when viewed from the top, where the off- center circular cutout and copper circular layer 304 is positioned proximal to the twelve o'clock position when viewed from the top, and the dipole 106 is proximal to a six o'clock position of the DRA cylinder 104 when viewed from the top.

According to a further embodiment of the invention, FIGs. 6a-6c show a DRA assembly 100 having a cusp layer 302 with an orientation that is capable of circular polarization operation. According to the current embodiment, a circular copper cusp 302 is placed on top of the DRA cylinder 104, where the circular copper cusp layer 302 has an outer diameter that is proximal to the silicon cylinder 104. The cusp layer 302 includes an off- center circular cutout therein, where the off-center circular cutout has a diameter that is smaller than the circular copper cusp layer 302 outer diameter, where the off-center circular cutout includes a copper circular layer 304 disposed therein, where the copper circular layer 304 has a diameter that is smaller than the off-center circular cutout diameter so as to fit within the cutout. According to one aspect of the current embodiment, the circular copper cusp layer 302 is positioned proximal a three o'clock position when viewed from the top, where the off-center circular cutout and copper layer 304 are positioned proximal to the three o'clock position when viewed from the top, where the off-center circular cutout and copper layer 304 are positioned to one side of the feeding line 108, where the magnetic dipole 106 along the substrate 102 bottom is disposed proximal to a center of the silicon cylinder 104 when viewed from the top, where the dielectric resonator antenna 100 is capable of circular polarization. According to one embodiment of the current example DRA assembly 100, the silicon substrate 102 has a thickness = 275 um. The current embodiment is available for high-resistivity silicon wafer only. The DRA cylinder 104 has a height = 400 μιη, and radius = 1.24 mm. The circular cusp 302 has dimensions as follows: i?cutout= 0.9 mm , Rin = 0.495 mm, 51 = 0.1525 mm, and S2 = 0.205 mm. Further, the CPW feeding line 108 that is deposited on bottom side of silicon substrate 102 has a slot width = 40 μιη, and distance between slots = 68 μιη ended by magnetic dipole 106 feeding the DRA cylinder 104. The dipole 106 has length (L) of 1.628 mm, and width (W) of 0.07 mm. The distance between the center of the feeding dipole 106 and that of the DRA cylinder 104 is 0 mm (see FIGs. la-lc and FIG. 4). In another embodiment, FIG. 6d shows the circular copper cusp layer 302 is positioned proximal a nine o'clock position when viewed from the top, where the off-center circular cutout and copper layer 304 are positioned proximal to the nine o'clock position when viewed from the top, where the off- center circular cutout and copper layer 304 are positioned to one side of the feeding line 108 (not shown), where the magnetic dipole 106 (not shown) along the substrate 102 bottom is disposed proximal to a center of the silicon cylinder 104 when viewed from the top, where the dielectric resonator antenna 100 is capable of circular polarization. According to a further embodiment, FIGs. 7a-7c show a DRA assembly 100 that is capable of circular polarization operation. According to the current embodiment, the circular copper cusp 302 is placed on top of the DRA cylinder 104, where the circular copper cusp layer 302 has an outer diameter that is proximal to the silicon cylinder 104. The cusp layer 302 includes an off-center circular cutout therein, where the off-center circular cutout has a diameter that is smaller than the circular copper cusp layer 302 outer diameter, where the off-center circular cutout includes a copper circular layer 304 disposed therein so as to fit within the cutout, where the copper circular layer 304 has a diameter that is smaller than the off-center circular cutout diameter. According to one aspect of the current embodiment, the circular copper cusp layer 302 is positioned proximal to a center position between a one o'clock position and a two o'clock position when viewed from the top, where the off-center circular cutout and copper layer 304 are positioned proximal to a center position between a one o'clock position and a two o'clock position when viewed from the top, where the off- center circular cutout and copper layer 304 are positioned to one side of the feeding line 108, where the magnetic dipole 106 along the substrate bottom is disposed proximal to a six o'clock position of the silicon DRA cylinder 104 when viewed from the top, where the dielectric resonator antenna 100 is capable of circular polarization. According to one example of the current embodiment, the silicon substrate 102 has a thickness = 275 μιη. The current embodiment is available for high-resistivity silicon wafer only. The DRA cylinder 104 has a height = 400 μιη, and radius = 1.115 mm. The circular copper cusp 302 is placed on top of the DRA cylinder 104, where the copper layer 304 is disposed in the circular cutout. The dimensions of the cusp is i?cutout = 0.83 mm, Rin = 0.38 mm, SI = 0.05 mm, and S2 = 0.05 mm, according to the current exemplary embodiment. The CPW feeding line 108, deposited on bottom side of silicon substrate 102, has a slot width = 40 μιη, and distance between slots = 68 μιη ended by magnetic dipole 106 feeding the DRA cylinder 104. The dipole 106 has length of 1.308 mm, and width of 0.037 mm. The distance between the center of the feeding dipole 106 and that of the DRA cylinder 104 center is 0.86 mm when viewed from the top (see FIGs. la-lc and FIG. 4). In another embodiment of the invention, FIG. 7d shows the circular copper cusp layer 302 is positioned proximal to a center position between a ten o'clock position and an eleven o'clock position when viewed from the top, where the off-center circular cutout and copper layer 304 are positioned proximal to a center position between a ten o'clock position and an eleven o'clock position when viewed from the top, where the off-center circular cutout and copper layer 304 are positioned to one side of the feeding line 108, where the magnetic dipole 106 (not shown) along the substrate bottom is disposed proximal to a six o'clock position of the silicon DRA cylinder 104 (not shown) when viewed from the top, where the dielectric resonator antenna 100 is capable of circular polarization.

The present invention has now been described in accordance with several exemplary embodiments, which are intended to be illustrative in all aspects, rather than restrictive. Thus, the present invention is capable of many variations in detailed implementation, which may be derived from the description contained herein by a person of ordinary skill in the art. All such variations are considered to be within the scope and spirit of the present invention as defined by the following claims and their legal equivalents.

Claims

claimed:

A dielectric resonator antenna, comprising:

a. a silicon cylinder;

b. a silicon substrate, wherein said silicon cylinder is disposed on said silicon substrate;

c. a magnetic dipole, wherein said magnetic dipole is disposed on a bottom side of said silicon substrate; and

d. a coplanar waveguide feeding line, wherein said coplanar waveguide feeding line is disposed on said bottom side of said silicon substrate, wherein said magnetic dipole terminates said coplanar waveguide feeding line.

2. The dielectric resonator antenna of claim 1, wherein said magnetic dipole is disposed proximal to an edge of said silicon cylinder and within said silicon cylinder when viewed from the top.

3. The dielectric resonator antenna of claim 1 further comprises a copper circular patch layer disposed on top of said silicon cylinder, wherein a diameter of said copper circular patch layer is smaller than a diameter of said silicon cylinder.

4. The dielectric resonator antenna of claim 1 further comprises a circular copper cusp layer disposed on said silicon cylinder, wherein said circular copper cusp layer has an outer diameter that is proximal to the diameter of said silicon cylinder wherein said cusp comprises an off-center circular cutout therein, wherein said off-center circular cutout has a diameter that is smaller than said circular copper cusp layer outer diameter, wherein said off-center circular cutout comprises a copper circular layer disposed therein, wherein said copper circular layer has a diameter that is smaller than said off-center circular cutout diameter.

5. The dielectric resonator antenna of claim 4, wherein said circular copper cusp layer is positioned proximal a six o'clock position when viewed from the top, wherein said off-center circular cutout is positioned proximal to said six o'clock position when viewed from the top, wherein said off-center circular cutout is positioned symmetric to said feeding line when viewed from the top, wherein said magnetic dipole along said substrate bottom is disposed proximal to a center of said silicon cylinder and proximal to an edge of said circular cutout when viewed from the top, wherein said dielectric resonator antenna is capable of linear polarization.

6. The dielectric resonator antenna of claim 4, wherein said circular copper cusp layer is positioned proximal a twelve o'clock position when viewed from the top, wherein said off-center circular cutout is positioned proximal to said twelve o'clock position when viewed from the top, wherein said off-center circular cutout is positioned symmetric to said feeding line when viewed from the top, wherein said magnetic dipole is disposed proximal to a six o'clock position of said silicon cylinder and said feeding lines are directed along said six o'clock position along said substrate bottom when viewed from the top, wherein said dielectric resonator antenna is capable of linear polarization.

7. The dielectric resonator antenna of claim 4, wherein said circular copper cusp layer is positioned proximal a three o'clock position when viewed from the top, wherein said off-center circular cutout is positioned proximal to said three o'clock position when viewed from the top, wherein said magnetic dipole is disposed proximal to a center of said silicon cylinder and said feeding lines are directed along said six o'clock position along said substrate bottom when viewed from the top, wherein said dielectric resonator antenna is capable of circular polarization.

8. The dielectric resonator antenna of claim 4, wherein said circular copper cusp layer is positioned proximal a center location between a one o'clock position and a two o'clock position when viewed from the top, wherein said off-center circular cutout is positioned proximal to said two o'clock position when viewed from the top, wherein said off-center circular cutout is positioned at an angle to said magnetic dipole when viewed from the top, wherein said magnetic dipole is disposed proximal to a six o'clock position of said silicon cylinder, wherein said feeding lines are directed along said six o'clock position along said substrate bottom when viewed from the top, wherein said dielectric resonator antenna is capable of circular polarization.

9. The dielectric resonator antenna of claim 4, wherein said circular copper cusp layer is positioned proximal a nine o'clock position when viewed from the top, wherein said off-center circular cutout is positioned proximal to said nine o'clock position when viewed from the top, wherein said magnetic dipole is disposed proximal to a center of said silicon cylinder and said feeding lines are directed along said six o'clock position along said substrate bottom when viewed from the top, wherein said dielectric resonator antenna is capable of circular polarization.

10. The dielectric resonator antenna of claim 4, wherein said circular copper cusp layer is positioned proximal a center location between a ten o'clock position and an eleven o'clock position when viewed from the top, wherein said off- center circular cutout is positioned proximal between said ten o'clock position and said eleven o'clock position when viewed from the top, wherein said off-center circular cutout is positioned at an angle to said magnetic dipole when viewed from the top, wherein said magnetic dipole is disposed proximal to a six o'clock position of said silicon cylinder, wherein said feeding lines are directed along said six o'clock position along said substrate bottom when viewed from the top, wherein said dielectric resonator antenna is capable of circular polarization.