WO2013025090A1

WO2013025090A1 - Wideband dielectric resonator antenna

Info

Publication number: WO2013025090A1
Application number: PCT/MY2011/000216
Authority: WO
Inventors: Mohd Fadzil AIN; Zainal Arifin AHMAD; Sabar Derita Hutagalung; Mohamad Ariff OTHMAN; Yazeed Mohamad AKRAM; Nazirul Izzat MOHD
Original assignee: Universiti Sains Malaysia
Priority date: 2011-08-12
Filing date: 2011-10-12
Publication date: 2013-02-21
Also published as: MY158714A

Abstract

The present invention discloses a wideband dielectric resonator antenna (1 ) with an exceptionally wide bandwidth of 2.30GHz and a center frequency of 8.19GHz. The wideband dielectric resonator antenna (1) of the present invention comprising of a dielectric resonator (4) made up of a plurality of vertically oriented slabs of dielectric material (4a) that are laterally stacked and disposed on strip of conductive material (3) that forms a portion of a micro-strip transmission line (7), aforementioned micro-strip transmission line (7) serving to feed electromagnetic signals that originate from a transmission circuit to the dielectric resonator (4) via SMA port connector (6). The exceptionally wide bandwidth of the wideband dielectric resonator antenna (1 ) of the present invention is attributed to the use of a plurality of vertically oriented, laterally stacked RT/duroid 6010LM dielectric material (4a) to form the dielectric resonator (4).

Description

WIDEBAND DIELECTRIC RESONATOR ANTENNA

The present invention relates to the field of antennae and electromagnetic wave propagation. More particularly the present invention relates to a dielectric resonator antenna mounted on a substrate with a ground plane. Most particularly the present invention relates to a dielectric resonator antenna with an exceptionally large bandwidth that makes it suitable for C-band and X-band applications.

BACKGROUND OF THE INVENTION

With the advancement of wireless communication technology, portable devices are being widely used in various applications that include industrial, scientific, and medical applications. The major requirements of these devices are portability and low power consumption. Therefore, the need to reduce the size and power consumption of the product becomes an important design consideration. For example, portable devices that operate based on the wireless LAN 802.11 a standard that stipulates a 5.25 GHz frequency band operation, usually adopt ordinary micro-strip antennas. The use of these types of antennas will result in excessive ohmic losses due to high operating frequencies.

Within the framework of the development of antennas associated with mass market products and used in domestic wireless networks, antennas consisting of a dielectric resonator have been identified as an interesting solution. Specifically, antennas of this type exhibit good properties in terms of pass-band and radiation. More particularly, the dielectric resonator antenna (DRA) has basically no ohmic loss, has the advantage of low loss rate, high radiation efficiency, high gain and is extremely suitable for high frequency applications. Moreover DRAs readily take the form of discrete components that can be surface mounted. Components of this type are known as SMC components. SMC components are of interest in the field of wireless communications for the mass market, since they allow the use of low-cost substrates, thereby leading to a reduction in cost while ensuring equipment integration. Moreover, when RF frequency functions are developed in the form of SMC components good performance is obtained despite the low quality of the substrate and integration is often favored thereby.

The dielectric resonator antenna or DRA consist of a dielectric patch of any shape, characterized by its relative permittivity. The resonant frequency is directly related to the dielectric constant which therefore conditions the size of the resonator. Thus the lower the permittivity, the more wideband the DRA antenna, but in this case, the component is bulky. However in the case of use in wireless communication networks, the compactness constraints, demand a reduction in size of dielectric resonator antennas, possibly leading to incompatibility with the bandwidths required for such applications.

Conventionally resonators with different shapes (for example resonators with a triangular and circular cross section) are stacked to increase bandwidth of dielectric resonator antennas. · <

Thus far there has yet to be developed a dielectric resonator antenna that operates appreciably over a large bandwidth (a bandwidth greater than 2GHz) for C-band and X-band applications. The C-band is a name given to certain portions of electromagnetic spectrum, including wavelengths of microwaves that are used for long distance radio telecommunications The IEEE C-band and its slight variations contains frequency ranges that are used for many satellite communications transmissions, some Wi-Fi devices, some cordless telephones, and some weather radar systems. The X band on the other hand is a segment of the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of X band is rather indefinitely set at approximately 7.0 to 11.2 gigahertz (GHz).

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

The present invention discloses a wideband dielectric resonator antenna with an exceptionally wide bandwidth of 2.30GHz and a center frequency of 8.19GHz. The wideband dielectric resonator antenna of the present invention comprising of a dielectric resonator made up of a plurality of vertically oriented slabs of dielectric material that are laterally stacked and disposed on a first working surface of a substrate material, the second working surface of the substrate material being coated substantially with a conductive material to serve as a partial ground plane of a micro- strip transmission line. The dielectric resonator is disposed on the first surface such that it is in direct electrical contact with a conductive strip of material that runs along the length of the first working surface. The combination of the conductive strip that runs along the length of the first working surface of the substrate, the dielectric substrate and the partial ground plane residing on the second working surface of aforementioned substrate form a micro-strip transmission line that serves as a feed line to feed electromagnetic signals from an electromagnetic signal transmission circuit via a SMA port connector to the dielectric resonator, the SMA port connector is electrically connected to the strip of conductive material of the first working surface and the partial ground plane of the second working surface.

The exceptionally wide bandwidth of the wideband dielectric resonator antenna of the present invention is attributed to the use of a plurality of vertically oriented, laterally stacked slabs of RT/Duroid 6010LM dielectric material to form the dielectric resonator. The relative permittivity of the RT/Duroid 6010LM dielectric material is 10.2. Aforementioned dielectric resonator and strip of conductive material are disposed in a generally central area of the first surface of aforementioned substrate material. The partial ground plane residing on the second working surface of the dielectric substrate configured as such, provides a significant radiation area and augments the dielectric resonator of the wideband dielectric resonator antenna of the present invention to provide a wide bandwidth and increased beam-width as compared to dielectric resonator antennas of the prior art. The wideband dielectric resonator antenna of the present invention utilizes a micro- strip transmission line feed, is simple and can be easily integrated into other planar circuits. It is widely used and is an easily manufactured antenna structure. Since the radiation pattern of the wide-band dielectric antenna of the present invention is omni- directional within the desired frequency band stipulated by WLAN requirements, it is suitable to be utilized in these applications.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 comprises of figures 1a and 1b, figure 1a is diagram illustrating the front view and figure 1 b is a diagram illustrating the rear view of the dielectric resonator antenna of the present invention;

Figure 2 is a diagram illustrating the side view of the dielectric resonator antenna of the present invention; < »

Figure 3 is a graph illustrating the measured insertion loss (S11 ) in (dB) as a function of frequency (GHz) of the dielectric resonator antenna of the present invention; Figure 4 is a graph illustrating the gain of the dielectric resonator antenna of the present invention obtained by way of computer simulation for values of gain falling in the frequency range of 4GHz to 12GHz;

Figure 5 comprises of figures 5a and 5b, wherein figure 5a is a polar plot illustrating the simulated E-field radiation pattern of the dielectric resonator antenna of the present invention, and figure 5b is a polar plot illustrating the measured E-field radiation pattern; and

Figure 6 comprises of figures 6a and 6b, wherein figure 6a is a polar plot illustrating the simulated H-field radiation pattern of the dielectric resonator antenna of the present invention, and figure 6b is a polar plot illustrating the measured H-filed radiation pattern. DETAILED DESCRIPTION OF THE INVENTION

The detailed description set forth below in connection with the appended drawings is intended as a description of an exemplary embodiment and is not intended to represent the only form in which the embodiment may be constructed and/or utilized. The description sets forth the functions and the sequence for constructing the exemplary embodiment. However, it is to be understood that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the scope of this disclosure.

By way of introduction dielectric resonator type antennas or DRA's must be able to ensure operation over a wide frequency range and typically consists of a dielectric patch of any-shape, characterized by its relative permittivity. The pass-band is directly related to the dielectric constant which therefore conditions the size of the resonator. Thus the lower the permittivity, the more wideband the DRA antenna, but in this case the component is bulky. In the case of use in wireless communication networks, the compactness constraint, demands a reduction in the size of the dielectric resonator.

The present invention will now be described with reference to figures 1 to 6. With reference to figures 1 and 2, the wideband dielectric resonator antenna 1 of the present invention is shown to comprise of a dielectric substrate material 2 of predefined thickness.'t' , the substrate material 2 including two working surfaces 1a, 1b. The first working surface 1a having a plane with a normal axis that extends in the vertically upward direction. The second working surface 1b of the wideband dielectric resonator antenna 1 of the present invention forms the underside of the wideband dielectric resonator antenna 1 of the present invention.

In a preferable embodiment of the wideband dielectric resonator antenna 1 of the present invention, the substrate material 2 is made of a dielectric material such as FR4, Teflon, Duroid, fiberglass, aluminum oxide, ceramic materials, and so on;

Aforementioned first working surface 1a of the wideband dielectric resonator antenna 1 of the present invention includes a strip of conductive material 3 that serves as a feed line to feed electromagnetic signals via a SMA connector port 6 to a dielectric resonator 4. Aforementioned conductive strip of material 3 running along the length of the first working surface 1a of the substrate 2 and is in direct electrical contact with aforementioned dielectric resonator 4. The combination of the dielectric resonator 4 and the conductive strip of material 3 being, disposed in a generally central area of the first working surface 1a of the substrate 2. Aforementioned second working surface 1b of the substrate material 2 of the wideband dielectric resonator antenna 1 of the present invention is substantially coated with a conductive material to form a partial ground plane 5. The combination of the first working surface 1a that includes a dielectric resonator 4 and the conductive strip of material 3 together with the dielectric substrate 2 and the second working surface 1b are electrically interconnected by the SMA port connector 6 and thus form a micro-strip transmission line 7 that is fed electromagnetic signals via aforementioned SMA port connector 6.

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As has been already mentioned in a preceding section of this description, the dielectric resonator 4 in dielectric resonator antennas are used to reduce the ohmic losses in antennas resulting from the high operating frequencies these antennas are subjected to, as in the case of LAN applications and applications that fall in the C-band and X- band spectrum of the electromagnetic spectrum. Conventionally, dielectric resonators 4 with different shapes (for example, resonators 4 with a triangular and circular cross section) are stacked to increase bandwidth of dielectric resonator antennas 1.

Accordingly the dielectric resonator 4 of the wideband dielectric resonator antenna 1 of the present invention, comprises of a plurality of vertically oriented slabs of dielectric material 4a of predefined thickness, width and length (i.e., of predefined dimensions) that are laterally stacked, each of the plurality of vertically oriented slabs of dielectric material 4a being in physical communication with an adjacent vertically oriented slab of dielectric material 4a.

In the wideband dielectric resonator antenna 1 of the present invention, aforementioned dielectric resonator 4 comprises of four slabs of vertically oriented, laterally stacked dielectric material 2, the dielectric material 2 being RT/Duroid 6010LM material with a relative permittivity of 10.2. Conventionally, resonators 4 with different shapes (for example, resonators with triangular and rectangular shapes) are stacked to increase bandwidth of dielectric resonator antennas 1. However, none of the prior art pertaining to dielectric resonator antennas 1 appear to disclose a wideband dielectric resonator antenna 1 with an exceptionally wide bandwidth of 2.33GHz.

The wideband dielectric antenna 1 of the present invention however discloses a wideband dielectric resonator antenna 1 that provides exceptionally wide bandwidth of 2.33GHz operable in the frequency range of 7.03 GHz to 9.36GHz and intended for operation in the C-band and X-band frequency ranges of the electromagnetic spectrum. It is the use of a plurality of vertically oriented, laterally stacked slabs of RT/Duroid 6010LM dielectric material 4a that enables the wideband dielectric antenna 1 of the present invention to be operable over such a aforementioned bandwidth.

In addition the partial ground plane 5 residing on the second working surface 1b of the dielectric substrate 2 configured as such, as described herein provides a significant radiation area and augments the dielectric resonator 4 of the wideband dielectric antenna 1 of the present invention to provide a wide bandwidth and increased beam- width as compared to dielectric resonator antennae of the prior art. The dimensional parameters of an exemplary embodiment of the wideband dielectric antenna 1 of the present invention are as tabulated below:-

Table 1 The following describes the various dimensional parameters of table 1.

The dimensional parameters W_D, L_D and HD refer to the width, length and height respectively of each layer of RT/Duroid 601 OLM dielectric material 4a used to construct the dielectric resonator 4 of an exemplary embodiment of the wideband dielectric resonator antenna 1 of the present invention.

The dimensional parameters L_M, H_M and W refer to the width, length and height respectively of the substrate material 2 which more particularly serves as a micro-strip transmission line 7 substrate material 2.

The dimensional parameters L_T, H_T and WT refer to the width, length and height respectively of the strip of conductive material 3 that resides on the first operating surface 1a of the dielectric substrate material 2 which forms a portion of the micro-strip transmission line 7 that serves as a feed line to feed electromagnetic signals to the dielectric resonator 4.

The dimensional parameters L_G, H_G and W_G refer to the width, length and height respectively of the ground plane residing on the second working surface 1 b of the dielectric substrate 2.

With reference to figure 3, over a frequency range of 4GHz to 12 GHz, the dielectric resonator antenna 1 of the exemplary embodiment described herein exhibits a minimal return loss at a resonant frequency of 8.20 GHz over an approximate bandwidth of 2.30GHz.

With reference to figure 4, over a measurement frequency range of 4GHz to 12 GHz, the dielectric resonator antenna 1 of the exemplary embodiment described herein, exhibits a gain of 5.32dB at the identified resonant frequency of 8.20GHz.

With reference to figures 5 and 6, figure 5 comprises of figures 5a and 5b, wherein figure 5a is a polar plot illustrating the simulated E-field radiation pattern of an exemplary embodiment of the dielectric resonator antenna 1 of the present invention as described herein, and figure 5b is a polar plot illustrating the measured E-field radiation pattern; and figure 6 comprises of figures 6a and 6b, wherein figure 6a is a polar plot illustrating the simulated H-field radiation pattern of the dielectric resonator antenna 1 of said exemplary embodiment of the present invention, and figure 6b is a polar plot illustrating the measured H-field radiation pattern.

With reference to both these figures (i.e., figures 5 and 6), it is observed from both the measured (measurements obtained from a working prototype of the wideband dielectric resonator antenna 1 of the present invention) and the simulated radiation pattern of an exemplary embodiment of the wideband dielectric resonator antenna 1 of the present invention as described herein, that the wideband dielectric resonator antenna 1 is omni-directional with a beam-width of 180°, thus enabling the wideband dielectric resonator antenna 1 of the present invention to receive electromagnetic signals within its 180° wide beam angle without having to re-orient or point to the signals every time the antenna 1 is displaced.

Claims

1. A wideband dielectric resonator antenna (1 ) that utilizes a resonator fabricated from a dielectric material to minimize ohmic losses in the Super High Frequency (SHF) range of frequencies ranging from 3GHz to 30GHz, comprising of : a micro-strip transmission line (7) that includes; a dielectric substrate (2) having a first working surface (1a) and a second working surface (1 b); a strip of conductive material (3) disposed on the first working surface ( a) of the dielectric substrate (2); and a ground plane (5) formed by coating the second working surface (1 b) of the dielectric substrate (2) with a conductive material; the combination of the strip of conductive material (3), dielectric substrate (2) and the ground plane (5) forming the micro-strip transmission line (7), the micro-strip transmission line (7) serving to receive electromagnetic signals from a transmission circuitry via a SMA port connector (6) that is in electrical contact with the strip of conductive material (3) of the first working surface (1a) and the ground plane (5) of the second working surface (1 b); and a dielectric resonator (4) disposed on the strip of conductive material (3) that resides on the first working surface (1 a) of the dielectric substrate (2) of the micro-strip transmission line (7) such that it is in electrical contact with the strip of conductive material (3) characterized in that; the dielectric resonator (2) is formed by laterally stacking a plurality of vertically oriented slabs of RT/Duroid 6010LM dielectric material (4a) of relative permittivity 10.2.

2. A wideband dielectric resonator antenna (1) according to claim 1 , wherein the ground plane (5) residing on the second working surface (1 b) of the dielectric substrate (2) is a partial ground plane (5).

3. A wideband dielectric resonator antenna (1 ) according to claim 1 , wherein the dielectric substrate (2) includes a FR4 substrate, a Teflon substrate, a fiberglass substrate and an aluminum oxide substrate.

4. A wideband dielectric resonator antenna (1) according to claim 1 , wherein the plurality of RT/Duroid 6010 LM dielectric slabs (4a) are laterally stacked and adhered to one another by utilizing an adhesive tape.

5. A wideband dielectric resonator antenna (1) according to claim 1 , wherein the dielectric resonator (4) is adhered to the strip of conductive material (3) of the first working surface (1a) of the dielectric substrate (2) by utilizing silicon adhesive.