Planar Slot Antenna Research Articles

A Novel “回” Pane Structure Multiband Microstrip Antenna for 2G/3G/4G/5G/WLAN/Navigation Applications

This work proposes a novel multiband slotted planar antenna with a “回” structure, which is similar to an ancient Chinese window grille structure. The antenna is suitable for wireless applications, including the second-generation (2G), third-generation (3G), fourth-generation (4G), and fifth-generation (5G) technologies, as well as WLAN and navigation applications. The proposed antenna is based on the structural characteristics of a conventional monopole antenna, which combines the advantages of a slit structure and microstrip line structure for feeding. It adopts a circular patch with a slit structure placed in it, which is similar to the Chinese classical pane structure. This structure enables an effective reduction of the size of the antenna. The four-sided “回” gaps change the path of current flow and are coupled to each other, improving the impedance matching and radiation characteristics of the entire target frequency band. The antenna covers the frequency ranges of 1.58–1.77 GHz (12%), 2.1–2.50 GHz (17%), 3.61–4.09 GHz (12%), and 4.75–6.5 GHz (36%), permitting more than 10 wireless applications in these 4 frequency bands. This antenna uses an FR-4 dielectric material; the relative dielectric constant of the dielectric plate is 4.4, and the actual dimensions of the antenna are 85 × 70 × 1.6 mm³. The test and simulation results are in good agreement with each other, thus confirming that the proposed design method meets the requirements of various wireless applications.

Optically controlled THz power tuning based on interference at transmission line.

We have proposed an optically controlled THz power tuning method based on THz wave interference. Through interfered THz waves at the T-junction transmission line, adjustment of the THz power is achieved, and tuning control is attained by varying the optical time delay of the beat-note lightwaves. To demonstrate and verify THz power tuning with an optical delay line, we have also fabricated a monolithic chip on an InP substrate, which integrates arrayed uni-traveling-carrier photodiodes and a planar slot antenna array for 300GHz wave generation. The experimental results reveal that the power transmission of this THz power tuner can be continuously adjusted with a wider tuning range than 7 dB at 300 GHz band. It should be a promising solution for the integration of compact THz wave planar photonic circuits.

Development of exact mathematic models for planar slotted traveling wave antennas using the dyadic Green function and their experiment foundation

Exact mathematic models were developed for traveling wave antennas with a constant slot width based on the dyadic Green function, taking into account both the main and cross-polarization components of the field in the far radiation zone. The possibility of using these models as basic models for studying the electrodynamic properties of traveling wave antennas with a different slot configuration (linearly, exponentially tapering, etc.) is justified. The influence of the geometric parameters of the investigated traveling wave antennas on their characteristics was studied by means of using the established mathematic models. It has been found that in the electrodynamic E plane, with an increase of the length and width of the slot, the main beam of the radiation pattern narrows, which leads to an increase the directed properties of the antennas. In the electrodynamic H plane, the width of the main beam of radiation pattern decreases only as the length of the slot of traveling wave antennas increases and does not depend on its width in practice. It was shown that the established theory results of the study are well consistent with the results of experiments, which also revealed the limitations of the applicability of the developed models. Analysis of traveling wave antennas characteristics was carried out at central frequency of 10 GHz in the frequency range of 8-12 GHz.

Theoretical and Experimental Study of the Electrodynamic Properties of Microwave Planar Slot Antennas

Mathematical models are developed for planar symmetric slot antennas (SAs) with constant slot width using a tensor Green function that takes into account both principal and cross-polarization components in the far-field zone. It is shown that such models can be employed in the study of the electrodynamic properties of SAs with different configurations of slots (linear, exponentially increasing, etc.). The mathematical models are used to analyze the effect of geometrical sizes of the slots in the SAs under study on the radiation patterns (RPs). It is shown that the calculated RPs are in good agreement with the experimental results that makes it possible to reveal applicability limits of the proposed mathematical models. The SAs are studied in the microwave range at a central frequency of 10 GHz.

A 90 GHz SINIS Detector With 2 GHz Readout

A superconductor-insulator-normal metal-insulator-superconductor (SINIS) detector integrated in a planar 90 GHz band twin-slot antenna with a 2 GHz superconducting resonator readout was fabricated and experimentally studied. In order to achieve high pixel count, the traditional dc readout of the SINIS detector is replaced by NbN coplanar 13.850 mm long superconducting resonator. SINIS detectors have traditionally dc Junction Field Effect Transistor (JFET) room-temperature readout. Such readout requires individual wiring for each pixel, while the microwave readout is far less cluttered as only one coaxial line is needed for hundreds of devices. Such readout operates similar to frequency domain multiplexing (FDM) for microwave kinetic inductance detectors (MKID). The planar twin slot antenna has two parallel slots in a metal ground plane which are excited coherently by short sections of a coplanar waveguide (CPW) line with a SINIS detector at the center. One section of the CPW is extended past the slot in a long superconducting section which functions as a quarter wavelength resonator. This resonator is short circuited to the ground plane at the far end, with the expected open circuited end terminated by the SINIS detector in the antenna. We measured the response of sample to black body radiation temperatures 6 K and 9 K. The corresponding dynamic resistance maximum drops from 50 kΩ down to 30 kΩ. An RF readout channel comprising a coplanar coupler and a coplanar resonator has a resonant frequency of 1.8 GHz. Unloaded Q factor (without incoming irradiation) is 200. The signal spectral characteristics and the response to the black body radiation have shown design values as expected.

Design of single‐fed spiral‐shaped slotted planar antenna for GPS L2 and L5 applications

An innovative design of a right hand circularly polarised (RHCP) antenna at two different resonant frequencies that is GPS (global positioning system) L2 and L5 has been proposed in this study. The proposed design comprised the concept of slotted radiator excited with a coaxial probe. Two asymmetric spiral slots were incorporated in a rectangular radiator to realise size miniaturisation, the axial ratio bandwidth and beamwidth at L2 (1.22760 GHz) and L5 (1.17645 GHz) frequencies of GPS applications. The proposed design has accomplished an excellent axial ratio bandwidth and beamwidth at both GPS L2 and L5 bands. The size of the designed antenna has been , which makes it attractive for the consumer market. Measured and simulated results achieved that the antenna conquered RHCP radiation at two separate operating bands, i.e. GPS L2 and L5.

Design procedure for planar slotted waveguide antenna arrays with controllable sidelobe level ratio for high power microwave applications

SummaryThis article presents a complete design procedure for planar slotted waveguide antennas (SWA). For a desired sidelobe level ratio (SLR), the proposed method provides a pencil shape pattern with a narrow half power beamwidth, which makes the proposed system suitable for high power microwave applications. The proposed planar SWA is composed of only two layers, and uses longitudinal coupling slots rather than the conventional inclined coupling slots. For a desired SLR, the slots excitation in the radiating and feeder SWAs are calculated based on a specified distribution. Simplified closed‐form equations are then used to determine the slots nonuniform displacements, for both the radiating and feeder SWAs, without the need to use optimization algorithms. Using simplified equations, the slots lengths, widths, and their distribution along the length of the radiating and feeder SWAs can be found. The feeder dimensions and slots positions are deduced from the dimensions and total number of the radiating SWAs. An 8 × 8 planar SWA has been designed and tested to show the validity of the proposed method. The obtained measured and simulated results are in accordance with the design objectives.

Design of Broadband High Gain Polarization Reconfigurable Fabry-Perot Cavity Antenna Using Metasurface

A broadband high gain polarization reconfigurable antenna based on metasurface has been presented. The antenna is composed of a planar metasurface, a slot antenna and an air cavity. The metasurface is made up of 64 identical patches, and all the patches are on the top surface of the substrate. The spatial equivalent circuit of the metasurface is discussed and two approximate calculation formulas of the equivalent circuit are obtained. The antenna can be reconfigured to linear polarization, left-hand and right-hand circular polarizations by adjusting the relative positions between the metasurface and the planar slot antenna. The gain of the antenna is improved. In order to verify these methods, the antenna is studied and designed to operate at around 11GHz. The simulated and measured results show that the 3dB axis ratio bandwidth is 10-12GHz (fractional bandwidth 18.18%) and maximum gain of 14.6dBi.

Half mode rogers RT duroid 5880 substrate integrated waveguide cavity backed V-slot antenna for C-band applications

A double band substrate integrated waveguide (SIW) and half-mode substrate integrated waveguide (HMSIW) with cavity backed planar slot antenna is proposed in this research work. The introduced antenna receives an aggregate of two SIW cavities of various dimensions through coupling window. The arrangement of V-shaped slots produces various hybrid modes, which can be adjusted by changing the size of the slot. The advantage of using V-shaped slots over U-shaped slots is improved return loss without affecting the central frequency. Two SIW cavities stacked with V-shaped slots are utilized to energize four firmly arranged hybrid modes in C band (4–8 GHz) to acknowledge double band reaction. The minimal HMSIW structure antenna even demonstrates a superior performance while decreasing almost half size of the SIW antenna.

A quad band planar slotted microstrip patch antenna for wireless applications

This research paper presents two different types of multiband patch antenna. The first design is a dual-band antenna and the second design is a quad-band antenna. Both the antennas have a compact size of , and is designed on FR4 substrate with loss tangent (=0.02, height (h)=1.6 mm, with dielectric constant of 4.4. The dual-band antenna operates at frequencies 3.9 and 5.71 GHz. These dual band operations are accomplished by utilizing L-shaped slot in the ground part and T-shaped slot in the radiating part of the patch antenna. The gain corresponding to the two frequency bands are 1.27 and 1.35 dB, respectively. The quad band antenna operates at frequencies 3.6, 4.9, 7.4 and 8 GHz. The gain corresponding to these frequencies are 0.18, 1.69, 2.25 and 3.99 dB. For achieving quad band operation from the dual band antenna the back plane L-shaped slot is modified by cutting a rectangular strip in the middle, hence dividing it into two different slots. The front plane is also modified by introducing two rectangular strips to the T-shaped patch. The proposed antenna shows multiband and has the advantage of simple structure compact size and good impedance matching. All the simulations of the proposed design are carried out in HFSS v.13.0.

Graphene-based materials for antenna applications

Internet of Things (IoT) has become one of the trending technologies in recent years. With the wide applications and rapid development of wireless communication and IoT, there are growing number of requirements on novel device design, such as flexible antennas and tunable antennas. The demand of transparent and flexible wireless communicational devices is ever-increasing for a wide range of scenarios, such as noninvasive healthcare, real-time wearable electronics, etc. Besides, a highly integrated antenna with tunable bandwidth and low energy consumption is in pressing demands in order to reduce the number of antennas and achieve better signal strength and higher speed signal transmission. Graphene materials have drawn much attention due to its extraordinary optical properties, high electrical and thermal conductivity, and excellent mechanical properties. All of these properties underline that graphene can be considered as a highly competitive material for wearable communication devices. Moreover, the electrical resistance of graphene and graphene oxide could be simply changed by external electric fields, applied strain and environment, which alters the electrical characteristics of the graphene-based microwave devices. Accordingly, graphene materials have a great potential in various reconfigurable or tunable devices. Our group fabricated the first graphene-based flexible and transparent wireless antenna with 2D large single-crystalline graphene and 1D AgNW hybrid material based on the features of graphene, such as high carrier mobility, transparency and flexibility, etc. The antenna exhibited a 75% light transmittance and an ultrawide bandwidth ranging from 5.6 to 12.8 GHz, combining with outstanding durability and stability with an almost negligible variation of reflection coefficients over 1000 bending cycles. Further research confirmed that the existence of graphene harmonized the compatibility between antenna and integrated chips, hence improved the total performance of the radio frequency identification (RFID) tags. Graphene/AgNW-based RFID tag was fabricated with an operating UHF band of 850–960 MHz and a reading distance of 130 cm, showing a great commercial potential. The excellent performance and unique properties of graphene/AgNW-based antenna and RFID tag came from the synergistic effect between 1D and 2D nanomaterials, providing a new vision for the design of next generation wireless electronics. Meanwhile, a slot antenna with tunable bandwidth was proposed. The antenna consisted of a planar slot antenna with graphene ink printed at the gap between the ground and a small patch. The graphene ink was made from the mixture of graphene powder and graphene oxide aqueous dispersion. Graphene oxide sheets functioned as effective surfactants rendering assistance to form uniform printable inks, displayed alterable electrical resistance by optimization of mixing proportions between graphene and graphene oxide. Dried graphene inks displayed tunable electrical resistance under applied DC voltages. The variation in the resistance of graphene ink affected radiation of the slot antenna, resulting in a shift of operating bandwidth. The proposed antenna achieved a shifting bandwidth of 0.54 from 6 to 5.46 GHz after applying DC voltage less than 15 V. Such cost-effective, easily acquired, and printable graphene inks integrated the dual advantages of graphene and graphene oxide. It could be further applied in many other fields of printable electronic devices.

A coplanar‐waveguide‐fed planar integrated cavity backed slotted antenna array using TE 33 mode

This short communication presents a substrate integrated waveguide planar cavity slotted antenna array. The proposed antenna array, excited in its TE33 higher mode, incorporates a grounded coplanar-waveguide (CPW) CPW-feeding excitation mechanism. The electromagnetic energy is coupled to the air through 3 × 3 slot array etched on top metallic layer. The proposed antenna operates in the X-band for the frequency range around the 10 to 11 GHz with resonances at 10.4 and 10.8 GHz frequencies. The proposed antenna array was fabricated and tested. Experimental results show good impedance matching with enhanced radiation characteristics, in terms of peak gain, cross-polarization level, and low back-radiation. The proposed antenna has the advantages of low-footprints, lightweight, high gain, low-cost, and ease of integration with other electronic circuits. With these characteristics, the proposed antenna array can find its applications in compact wireless digital transceivers.

A superconducting flux-flow oscillator of terahertz range

We have elaborated, fabricated and tested a THz source radiating to open space based on the superconducting flux-flow oscillator (FFO). In this concept, the oscillator is integrated with the transmitting lens antenna based on a slot structure in Nb film with a thickness of ~200 nm located on the same chip. The slot planar antenna is matched to the oscillator (by input) and to the semielliptical Si lens with a diameter of 10 mm (by output) providing a narrow output beam of THz emission. A harmonic mixer based on the superconductor-insulator-superconductor junction embedded in the “FFO and antenna” integrated structure has been used for the phase locking of the oscillator. Several designs of antenna coupled with the oscillator by microstrip lines have been numerically simulated, and the batches of experimental samples based on Nb-AlN-NbN superconducting trilayers with Rn ·A ~ 20 Ω·μm2 (jc ~ 10 kA/cm2) have been fabricated and tested. Two different setups were used for experimental study: a THz spectrometer based on the SIS receiver with a high spectral resolution (better than 0.1 MHz) and a Si bolometer. The overall operating range of 250 to 700 GHz is covered by all the developed designs.

A 94-GHz FMCW Radar Receiver Based on Low-Barrier Diode

A receiver based on a low-barrier diode has been developed for use in a 94-GHz frequency-modulated continuous-wave radar. The receiver has a very simple design with the radio frequency (RF) front-end consisting of only a mixing diode mounted on a planar slot antenna. The low-barrier diode operates at a zero bias, and thus, the RF front end does not require any power supply. A transimpedance amplifier transforms the mixer intermediate frequency current into voltage, which is the output signal of the receiver module. The receiver works at a low local oscillator (LO) power keeping conventional performance: A noise-equivalent power of 1.4 × 10–19 W/Hz at an LO power of 0.1 mW is achieved.

Compact Folded Slot Antenna and Its Endfire Arrays With High Gain and Vertical Polarization

A novel folded slot antenna is proposed for the design of high-gain and compact endfire arrays. This letter shows that a planar slot antenna retains bidirectional radiation characteristics when folded into a compact structure. A folded slot antenna was designed in order to obtain a high endfire gain of 6 dBi. The proposed slot antenna's high gain makes it a good candidate for designing endfire arrays with vertical polarization. A series-fed technique is proposed in order to design two-element endfire and backfire arrays. Subsequently, an eight-element endfire array is proposed by combining endfire and backfire two-element arrays. The eight-element array is capable of producing a high endfire gain of 13.2 dBi with a size of 1.8λ0 × 1.4λ0, which is less than half the size of the existing endfire antennas with similar vertically polarized gain.

Wideband tapered slot antenna for applications in ground penetrating radar

AbstractA planar slotted patch antenna is proposed for ground penetrating radar (GPR). The proposed antenna has a wide bandwidth ranging from 600 MHz to 4 GHz. Tapered slot feeding, curved ground plane, and slot loading are used for a wideband operation, whereas resistive loading is utilized for removal of notch band. Current loops made by slots are bifurcated with the use of 50 Ω resistors. The antenna is designed and optimized to achieve good performance, especially at lower frequencies while keeping the antenna's physical dimension relatively small. The time‐domain analysis of the antenna is performed, and the comparative graph is added after analysis to validate its performance in the impulse‐based radar. Furthermore, a sandbox test is conducted; the experimental results show the significance of the proposed antenna toward GPR application.

A multi-band SIW based antenna for wireless communication

ABSTRACT This paper presents the design and development of planar triplexer slot antenna using substrate integrated waveguide (SIW) technology. The proposed antenna is realised using ‘Y’ shaped slot backed by SIW cavity. SIW cavity is excited by three separate feed lines for resonance at three different frequencies of 5.7 GHz, 6 GHz and 6.4 GHz with unidirectional radiation pattern and gain of 6.26 dBi, 5.87 dBi and 5.19 dBi, respectively. Average isolation of the three ports is better than 24 dB. All the simulations are carried out using high frequency structure simulation (HFSS) software. The proposed antenna is fabricated on RT Duroid 5880substrate and measured results show better performance. The developed antenna is small in size (0.79 × 0.78), simple to fabricate and easy to integrate with planar technology making it suitable for C-band application.

A technique for reduction of mutual coupling by steering surface wave propagation

AbstractIn this article, we present an efficient approach to reduce mutual coupling in a planar slot antenna array by using high refractive index metamaterial. The metamaterial structure is employed to steer the propagation of the surface wave. For this purpose, array of complementary slot coupled split‐ring resonator structures are designed on the two sides of the slot array. The proposed configuration is fabricated and both simulation and measurement results confirm that an average of 10 dB improvements in isolation level is achieved throughout the wide operating bandwidth. Moreover, due to the implementation of the complementary metamaterial structure, the proposed configuration becomes planar and easy to fabricate.

Broadband planar slot antenna using a simple single‐layer FSS stopband

In this study, the authors propose a simple structure of a new broadband planar slot antenna using a wide single-layer frequency selective surface (FSS) stopband. The proposed design is realised in two stages. First, the performances of the FSS unit cells are investigated using the finite element method of high-frequency structure simulator. Besides, the FSS structure considered as a stop-band filter in the bandwidth , is also validated by computer simulation technology microwave studio. Second, this FSS reflector is combined with a miniaturised wideband planar slot antenna . The final proposed combination is also designed, optimised, fabricated and validated by measurements. The obtained results show an operating impedance bandwidth of including the Worldwide interoperability for Microwave Access band, the C band for satellite applications, and the Wireless Local Area Network band. Furthermore, the antenna provides an measured maximum gain. Compared to the same antenna without FSS, a maximum gain enhancement of is achieved by the proposed structure. In addition, the back lobes are reduced in the proposed structure by , compared to a simple antenna. The total size of the proposed antenna, integrating the FSS, is .

Dual band circular polarized bow tie slotted patch antenna over high impedance surface for WiMAX application

AbstractA novel planar dual-band bow-tie slotted patch antenna backed by high-impedance surface (HIS) is designed at 2.5 and 3.5 GHz for wireless application. The antenna employs coplanar waveguide fed patch and bow-tie slot as radiating elements. The bow-tie slot enables dual-band operation for the antenna. The HIS is made asymmetric in design to make it polarization dependent. This polarization-dependent HIS is eventually designed to reflect circularly polarized waves from linearly polarized incident waves.