Aspects of the present disclosure were described in Rifaqat Hussain, “Shared-Aperture Slot-Based Sub-6-GHz and mm-Wave IoT Antenna for 5G Applications” published in IEEE Internet of Things Journal, Vol. 8, No. 13, pp. 10807-10814, 2021.
The present disclosure is directed to an aperture shared slot-based sub-6 GHz and mm-wave IoT antenna for 5G applications.
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Introduction and expansion of various wireless services have resulted in a surge in the use of wireless terminals such as cell phones, tablets, and various personal digital assistants (PDAs). Wireless devices with internet connectivity and higher data throughput are demanded by users so that the wireless devices can experience multimedia and video streaming. The demand for higher data rates will continue to rise as the world is moving towards fifth-generation (5G) and sixth-generation (6G) wireless standards. Internet of Things (IoT) is a new paradigm for the next-generation 5G technology that is stated to bring connectivity to a plurality of small devices to the Internet. IoT is a platform that supports numerous interconnected wireless devices embedded with, for example, radio-frequency (RF) sensors, an electronic circuitry, and antenna systems.
A Multiple-Input Multiple-Output (MIMO) antenna is used extensively in the 5G standard, as it is compatible with the previous generation (4G). The MIMO antenna covers wide ranges and is compatible with short-range communication standards, including millimeter-wave (mm-wave) bands (having a frequency range of 30 to 300 GHz). The MIMO antenna provides ultra-high throughput over short distances, allowing real-time multimedia and video transfers, and further achieving the anticipated increase in data rates.
As the size of wireless terminals is small, space used for an antenna is fairly limited. The antenna is internally integrated into the wireless terminal. As 5G technology is developed, more and more MIMO sub-antenna units are required to be integrated into the limited space of the wireless terminal. As the number of the sub-antenna units increases, the spacing of the sub-antenna unit is reduced, such that strong surface waves and spatial inductive coupling occur between the sub-antennas, thereby deteriorating the performance of the MIMO antenna.
In order to reduce the coupling between multiple sub-antenna units, a variety of decoupling technologies have been introduced. In some examples, the coupling between antennas can be effectively reduced using technologies such as decoupling circuits and decoupling networks. However, the decoupling circuits and decoupling networks would require additional space. Further, there are also several other antenna design challenges, including its small, compact size for miniaturized IoT devices, multi-standard antenna with a low-profile structure, and reduced cost. An available IoT antenna is capable of operating at various frequency bands. These IoT antennas include low profile, compact, multi-standard IoT antennas with various sub-6-GHz frequency coverage. Such IoT antennas include printed monopoles, inverted-F antennas, loops, and patch-based designs.
Most of the available antennas for IoT applications are either working in sub-6-GHz bands or mm-wave bands. Hence, there is a need for an IoT antenna for 5G applications that can operate in wide-band operation covering both sub-6-GH band and mm-wave band.
In an exemplary embodiment, an antenna system is described. The antenna system includes a substrate having a top side and a bottom side, and a single straight microstrip line on the top side of the substrate. An input end of the single straight microstrip line is adjacent and vertical to a first edge of the substrate, and an output end of the single straight microstrip line is open. The antenna system further includes a microstrip power divider (PD) on the top side of the substrate. An input end of the microstrip PD is adjacent and vertical to a second edge of the substrate, eight output ends of the microstrip PD are open, and the first edge is parallel to the second edge. The antenna system further includes a ground plane on the bottom side. Three concentric square slots are etched on the ground plane.
In another exemplary embodiment, a method of fabricating an antenna system is described. The method includes generating a single straight microstrip line on a top side of a substrate of the antenna system. An input end of the single straight microstrip line is adjacent and vertical to a first edge of the substrate, and an output end of the single straight microstrip line is open. The method further includes generating a microstrip power divider (PD) on the top side of the substrate. An input end of the microstrip PD is adjacent and vertical to a second edge of the substrate, eight output ends of the microstrip PD are open, and the first edge is parallel to the second edge. The method further includes generating a ground plane on a bottom side of the substrate. Three concentric square slots are etched on the ground plane.
In another exemplary embodiment, a non-transitory computer-readable storage medium storing a program executable by at least one processor to perform: generating a single straight microstrip line on a top side of a substrate of the antenna system, an input end of the single straight microstrip line being adjacent and vertical to a first edge of the substrate, and an output end of the single straight microstrip line being open; generating a microstrip power divider (PD) on the top side of the substrate, an input end of the microstrip PD being adjacent and vertical to a second edge of the substrate, eight output ends of the microstrip PD being open, and the first edge being parallel to the second edge; and generating a ground plane on a bottom side of the substrate, three concentric square slots being etched on the ground plane.
The foregoing general description of the illustrative embodiments and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure, and are not restrictive.
A more complete appreciation of this disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
In the drawings, like reference numerals designate identical or corresponding parts throughout the several views. Further, as used herein, the words “a,” “an” and the like generally carry a meaning of “one or more,” unless stated otherwise.
Furthermore, the terms “approximately,” “approximate,” “about,” and similar terms generally refer to ranges that include the identified value within a margin of 20%, 10%, or preferably 5%, and any values therebetween. For example, descriptions of dimensions and/or properties such as “about 50 mm” or “about 3.48” include ranges of 50 mm±20%, 10% or 5%, and 3.48±20%, 10% or 5%, respectively.
Aspects of this disclosure are directed to an antenna system and a method of fabricating the antenna system. The present disclosure describes a square shaped concentric slot-based antenna for sub-6-GHz and millimeter-wave (mm wave) 5G-enabled Internet of Things (IoT) devices. The described antenna exhibits an octaband operation for the sub-6-GHz spectrum while it resonates at 28 GHz as well. The described antenna has a shared radiating aperture for both sub-6-GHz as well as mm-wave bands. The antenna includes three concentric square slots etched out from a ground (GND) plane dimension of 50×50×0.508 mm3. For the sub-6-GHz band, the antenna is excited by a single open-ended microstrip transmission line, while 1×8 power divider (PD) is used to excite the planar connected antenna arrays at the mm-wave band. The described antenna covers eight bands for sub-6-GHz operation: 1.05-1.23 GHz; 1.4-1.55 GHz; 1.9-2.3 GHz; 2.3-2.7 GHz; 3.1-3.7 GHz; 4.04-4.511 GHz; 4.83-5.2 GHz; and 5.66-6.151 GHz. The mm-wave band covers 27.4-28.4 GHz with a minimum bandwidth (BW) of 1 GHz. The described antenna covers most of the IoT bands; thus, it is a potential candidate for next-generation 5G-enabled IoT devices.
The substrate 102 has a top side 104 and a bottom side 106. In an aspect, the substrate 102 is a Rogers RO4350 substrate (fabricated by Roger cooperation, located at 2225 W Chandler Blvd, Chandler, Ariz. 85224). The Rogers RO4350 substrate is used due to its low relative permittivity (εr) and ease of milling the substrate using an LPKF S103 (manufactured by LPKF Laser & Electronics, located at Osteriede 7, 30827 Garbsen, Germany). Further, the substrate 102 has a first edge 112 and a second edge 118. In an aspect, the first edge 112 is parallel to the second edge 118. In an aspect, the size of the substrate 102 is 50×50 mm2. In some examples, the substrate 102 has a dielectric constant of 3.48, a loss tangent of 0.0036, and a thickness of 0.508 mm.
The single straight microstrip line 108 is fabricated on the top side 104 of the substrate 102 via a laser milling process for example. The single straight microstrip line 108 includes an input end 110 and an output end 124. The input end 110 is adjacent to the first edge 112 of the substrate 102. The input end 110 is also vertical (perpendicular) to the first edge 112 of the substrate 102. Further, the output end 124 of the single straight microstrip line 108 is open. In an aspect, the length of the single straight microstrip line 108 is 15.3 mm and the width of the single straight microstrip line 108 is 1.4 mm. In an aspect, the size of the single straight microstrip line is 15.3×1.4 mm2. The single straight microstrip line 108 acts a feed-1 for the antenna 100 as shown in
The microstrip power divider (PD) 114 is also fabricated on the top side 104 of the substrate 102 using the laser milling process for example. In an aspect, the microstrip PD 114 is a cascaded 8-way power divider. The power divider is a passive device that is used to couple a defined amount of electromagnetic power in a transmission line via a port enabling the signal to be used in another circuit. In a structural aspect, the microstrip PD (1×8 power divider) 114 has an input end 116 and eight output ends 120. The input end 116 of the microstrip PD 114 is adjacent and vertical to the second edge 118 of the substrate 102. The eight output ends 120 of the microstrip PD 114 are open. The 1×8 microstrip PD 114 acts a feed-2 for the antenna 100 as shown in
The ground plane 122 is fabricated on the bottom side 106 of the substrate 102 (as shown in
Slot-based frequency-reconfigurable (FR) antennas are selected because of their low-profile planar structure, ease of integration, and capability to be operated over a wide frequency band. Both open ended slot and closed ended slot designs have been reported in the related arts. The slot antenna with short circuited or closed ends may be modeled as λ/2 transmission line, corresponding to its fundamental resonance frequency. Such antennas may be effectively loaded with the capacitive reactance and its resonance frequencies may be changed over a wideband. The fundamental resonance frequency of the rectangular slot antenna is given by:
where c is the speed of light in free space, εr is the relative permittivity of the substrate, fr is the fundamental resonance frequency of the modified rectangular ring slot antenna 100, and the term 2(l2+l1) is the mean circumference of the modified rectangular ring slot antenna 100.
Moreover, several other important parameters are also considered for the antenna design, as follows:
1) Slot dimensions of each square slot (S1-S3) correspond to the fundamental resonance frequency of each band.
2) Width and length of microstrip line: The dimension is an important factor in obtaining the octaband operation in sub-6-GHz bands with good input impedance matching.
3) The design of PD is also an important factor as the PD helps in tuning the antenna at the desired band.
4) Length and width of the substrate 102 are also important factors. Further, a sufficient clearance is required on both sides of the board such that resonating bands are not affected.
Each slot of the square slot-line structure (S1-S3) is represented by its corresponding fundamental resonating frequencies f1, f2, and f3, while higher-order excitation modes have their corresponding resonating frequencies as f4, f5, . . . , f8. The microstrip line 108 may be represented by a series combination of an Lf, Cf circuit (shown by 302) that energized the concentric square slots (S1-S3). The complete circuit diagram 300 helps in understanding the multiband operation of the concentric square slot antenna structure 100. From the circuit diagram and antenna's analysis, the octaband resonances are easily understood. The circuit element values can be extracted using the ADS simulation technique by utilizing the S-parameters of the antenna 100.
The following examples are provided to illustrate further and to facilitate the understanding of the present disclosure.
The shared-aperture slot-based mm-wave and sub-6-GHz antenna 100 was modeled and simulated using HFSS (High Frequency Structure Simulator). The antenna design was fabricated and characterized for S-parameters as well as for radiation patterns. All simulated and measured results are described herein:
First Experiment: Antenna Scattering Parameters
In the first experiment, the simulated and measured scattering parameters of both mm-wave and sub-6-GHz antenna designs were considered. The described sub-6-GHz antenna 100 was improved to get the maximum number of tuned bands (for example, eight bands in this case) in the sub-6-GHz spectrum, while improved performance was achieved at the mm-wave band at 28 GHz.
The improved antenna design was fabricated using an LPKF (S-103) prototyping machine (manufactured by LPKF Laser & Electronics, located at Osteriede 7, 30827 Garbsen, Germany). The scattering parameters of the antenna 100 were measured using the Agilent PNA-N5227A network analyzer (manufactured by Agilent Technologies/Keysight Technologies, located at 1400 Fountaingrove Parkway, Santa Rosa, Calif. 95403-1738) for both the sub-6-GHz band and the millimeter-wave band.
Second Experiment: Current Density Analysis
In order to characterize the octaband sub-6-GHz operation of the antenna 100, the surface current distributions were investigated at various resonating bands in the second experiment.
Third Experiment: Radiation Patterns
The antenna 100 was characterized for its radiation characteristics at different frequency bands.
The maximum values of the gain for sub-6-GHz bands were varied from 1.1 to 5.3 dBi. The simulated and measured peak gain values and efficiency (%η) for the antenna 100 are shown in Table I.
For both bands, i.e., sub-6-GHz and the mm-wave bands, the antenna efficiency (%η) is between 65% and 92%. The design of the antenna 100 is the multiband antenna design. Each concentric slot (S1-S3) resonates at the fundamental and higher-order modes. The %η of the fundamental mode is higher than the higher-order modes. The described antenna 100 operates in the fundamental mode at 5.8 GHz, while the higher-order mode operates at 28 GHz.
Step 902 includes generating a single straight microstrip line 108 on a top side 104 of a substrate 102 of the antenna system 100. An input end 110 of the single straight microstrip line 108 is adjacent and vertical to a first edge 112 of the substrate 102, and an output end 124 of the single straight microstrip line 108 is open. In an aspect, a dielectric constant of the substrate 102 is 3.48, a loss tangent of the substrate 102 is 0.0036, and a thickness of the substrate 102 is 0.508 mm. In an aspect, a size of the single straight microstrip line is 15.3×1.4 mm2. For the sub-6-GHz band, the antenna 100 is excited by the single open-ended microstrip transmission line 108.
Step 904 includes generating a microstrip power divider (PD) 114 on the top side 104 of the substrate 102. An input end 116 of the microstrip PD 114 is adjacent and vertical to a second edge 118 of the substrate 102, eight output ends 120 of the microstrip PD 114 are open, and the first edge 112 is parallel to the second edge 118. In an aspect, the microstrip PD 114 is a cascaded 8-way power divider. In an aspect, a size of the substrate 102 is 50×50 mm2. The 1×8 power divider (PD) 114 is used to excite the planar connected antenna arrays at the mm-wave band.
In an aspect, the input end 110 of the single straight microstrip line 108 is excited with a sub-6GHz frequency, and the input end 116 of the microstrip PD 114 is excited with a millimeter-wave frequency.
Step 906 includes generating a ground plane 122 on a bottom side 106 of the substrate 102. Three concentric square slots (S1-S3) are etched on the ground plane 122. In an aspect, lengths of the three concentric square slots (S1-S3) are 33.33 mm, 28.93 mm, and 23.43 mm, respectively, the widths of the three concentric square slots (S1-S3) are all 0.5 mm, and spaces between every two adjacent concentric square slots are 2 mm and 2.5 mm, respectively.
Similarly,
The radiation characteristics of the shared-aperture slot-based antenna design at the mm-wave band are shown in
As shown in
Specifically, the main reasons for the slight differences in the simulated and measured results are because of several reasons listed as:
1) Fabrication Tolerances: Differences in the dimensions of the antenna due to fabrication may affect the results.
2) Different εr Values: Any difference in the εr values of the same substrate might result in large deviation in antenna geometry at mm-wave bands.
3) Connectors Soldering: The slight variation in manual soldering introduced noise that may change the antenna characteristics.
4) Selecting Antennas Material: To achieve high performance of antennas implementation, it is desirable to enhance the radiation efficiency and robustness of the board. This reduces the flexibility of selecting any particular material for the antenna design.
5) Mass Production of Antenna Designs: Consistency in the production of antenna designs is highly desirable.
Also, an IoT antenna design operating at the sub-1-GHz band with a compact form factor, is a challenging requirement. Such an integrated low-profile antenna solution at sub-1 GHz and mm-wave will be highly recommended in futuristic devices.
The first embodiment is illustrated with respect to
In an aspect, a dielectric constant of the substrate 102 is 3.48, a loss tangent of the substrate 102 is 0.0036, and a thickness of the substrate 102 is 0.508mm.
In an aspect, the microstrip PD 114 is a cascaded 8-way power divider.
In an aspect, a size of the substrate 102 is 50×50 mm2.
In an aspect, a size of the single straight microstrip line 108 is 15.3×1.4 mm2.
In an aspect, lengths of the three concentric square slots (S1-S3) are 33.33 mm, 28.93 mm, and 23.43mm, respectively, widths of the three concentric square slots (S1-S3) are all 0.5 mm, and spaces between every two adjacent concentric square slots are 2 mm and 2.5 mm, respectively.
In an aspect, the input end 110 of the single straight microstrip line 108 is excited with a sub-6GHz frequency, and the input end 116 of the microstrip PD 114 is excited with a millimeter-wave frequency.
The second embodiment is illustrated with respect to
In an aspect of the present disclosure, a dielectric constant of the substrate is 3.48, a loss tangent of the substrate is 0.0036, and a thickness of the substrate is 0.508 mm.
In an aspect of the present disclosure, the microstrip PD is a cascaded 8-way power divider.
In an aspect of the present disclosure, a size of the substrate is 50×50 mm2.
In an aspect of the present disclosure, a size of the single straight microstrip line is 15.3×1.4 mm2.
In an aspect of the present disclosure, lengths of the three concentric square slots are 33.33 mm, 28.93 mm, and 23.43 mm, respectively, widths of the three concentric square slots are all 0.5 mm, and spaces between every two adjacent concentric square slots are 2 mm and 2.5 mm, respectively.
In an aspect of the present disclosure, the input end of the single straight microstrip line is excited with a sub-6GHz frequency, and the input end of the microstrip PD is excited with a millimeter-wave frequency.
The third embodiment is illustrated with respect to
In an aspect, a dielectric constant of the substrate is set as 3.48, a loss tangent of the substrate is set as 0.0036, and a thickness of the substrate is set as 0.508 mm.
In an aspect, the microstrip PD is generated as a cascaded 8-way power divider.
In an aspect, a size of the substrate is set as 50×50 mm2.
In an aspect, a size of the single straight microstrip line is set as 15.3×1.4 mm2.
In an aspect, lengths of the three concentric square slots are set as 33.33 mm, 28.93 mm, and 23.43 mm, respectively, widths of the three concentric square slots are all set as 0.5 mm, and spaces between every two adjacent concentric square slots are set as 2 mm and 2.5 mm, respectively.
Next, further details of the hardware description of the computing environment of
Further, the claims are not limited by the form of the computer-readable media on which the instructions of the inventive process are stored. For example, the instructions may be stored on CDs, DVDs, in FLASH memory, RAM, ROM, PROM, EPROM, EEPROM, hard disk or any other information processing device with which the computing device communicates, such as a server or computer.
Further, the claims may be provided as a utility application, background daemon, or component of an operating system, or combination thereof, executing in conjunction with CPU 1401 (and/or CPU 1403) and an operating system such as Microsoft Windows 7, Microsoft Windows 10, UNIX, Solaris, LINUX, Apple MAC-OS and other systems known to those skilled in the art.
The hardware elements in order to achieve the computing device may be realized by various circuitry elements, known to those skilled in the art. For example, the CPU 1401 and/or the CPU 1403 may be a Xenon or Core processor from Intel of America or an Opteron processor from AMD of America or may be other processor types that would be recognized by one of ordinary skill in the art. Alternatively, the CPU 1401 and/or the CPU 1403 may be implemented on an FPGA, ASIC, PLD or using discrete logic circuits, as one of ordinary skilled in the art would recognize. Further, the CPU 1401 and/or the CPU 1403 may be implemented as multiple processors cooperatively working in parallel to perform the instructions of the inventive processes described above.
The computing device in
The computing device further includes a display controller 1408, such as a NVIDIA GeForce GTX or Quadro graphics adaptor from NVIDIA Corporation of America for interfacing with display 1410, such as a Hewlett Packard HPL2445w LCD monitor. A general purpose I/O interface 1412 interfaces with a keyboard and/or mouse 1414 as well as a touch screen panel 1416 on or separate from display 1410. General purpose I/O interface also connects to a variety of peripherals 1418 including printers and scanners, such as an OfficeJet or DeskJet from Hewlett Packard.
A sound controller 1420 is also provided in the computing device such as Sound Blaster X-Fi Titanium from Creative, to interface with speakers/microphone 1422 thereby providing sounds and/or music.
The general purpose storage controller 1424 connects the storage medium disk 1404 with communication bus 1426, which may be an ISA, EISA, VESA, PCI, or similar, for interconnecting all of the components of the computing device. A description of the general features and functionality of the display 1410, keyboard and/or mouse 1414, as well as the display controller 1408, storage controller 1424, network controller 1406, sound controller 1420, and general purpose I/O interface 1412 is omitted herein for brevity as these features are known.
The exemplary circuit elements described in the context of the present disclosure may be replaced with other elements and structured differently than the examples provided herein. Moreover, circuitry configured to perform features described herein may be implemented in multiple circuit units (e.g., chips), or the features may be combined in circuitry on a single chipset, as shown on
In
For example,
Referring again to
The PCI devices may include, for example, Ethernet adapters, add-in cards, and PC cards for notebook computers. The Hard disk drive 1560 and CD-ROM666 can use, for example, an integrated drive electronics (IDE) or serial advanced technology attachment (SATA) interface. In one implementation the I/O bus can include a super I/O (SIO) device.
Further, the hard disk drive (HDD) 1560 and optical drive 1566 can also be coupled to the SB/ICH 1520 through a system bus. In one implementation, a keyboard 1570, a mouse 1572, a parallel port 1578, and a serial port 1576 can be connected to the system bus through the I/O bus. Other peripherals and devices that can be connected to the SB/ICH 1520 using a mass storage controller such as SATA or PATA , an Ethernet port, an ISA bus, a LPC bridge, SMBus, a DMA controller, and an Audio Codec.
Moreover, the present disclosure is not limited to the specific circuit elements described herein, nor is the present disclosure limited to the specific sizing and classification of these elements. For example, the skilled artisan will appreciate that the circuitry described herein may be adapted based on changes on battery sizing and chemistry, or based on the requirements of the intended back-up load to be powered.
The functions and features described herein may also be executed by various distributed components of a system. For example, one or more processors may execute these system functions, wherein the processors are distributed across multiple components communicating in a network. The distributed components may include one or more client and server machines, which may share processing, as shown by
The above-described hardware description is a non-limiting example of corresponding structure for performing the functionality described herein.
Obviously, numerous modifications and variations of the present disclosure are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
The present disclosure claims the benefit of U.S. Provisional Application No. 63/292,100, “APERTURE SHARED SLOT-BASED SUB-6 GHZ AND MM-WAVE IOT ANTENNA FOR 5G APPLICATIONS” filed on Dec. 21, 2021, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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63292100 | Dec 2021 | US |