Coplanar Ground Research Articles

Compact wide dual-band square dielectric resonator antenna to serve X-band/emerging 5G communication

This communication presents a new dual-band, compact, and low-cost square-shaped dielectric resonator antenna (SDRA). A square dielectric, Alumina_96 pct of compact dimension 10 × 10× 3 mm3 is mounted on the coplanar ground on the top of the substrate RO4003. The antenna is excited by employing the aperture coupling method via a rectangular-ring slot. This newly designed slot-coupled SDRA exhibits wide dual-band characteristics, resonating at frequencies 8.65 GHz and 11.08 GHz. The proposed compact SDRA is fabricated. The fabricated SDRA is measured for evaluation of its performance parameters. The measured results are fairly matching with the simulation results. The gain and efficiency at 8.65 GHz in the lower band are measured as 6.25 dBi and 96 %, respectively. The gain of the upper band is maintained at 4.32 dBi with an efficiency of 94.56 %. Measured stable far-field outcomes validate the suggested SDRA suitable for X-Band/emerging 5G Communication.

CPW-Fed UWB-MIMO Antenna with Triple-band Notched and High Isolation using Double Y-shaped Decoupling Structure

A ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna using double Y-shaped decoupling structure with high isolation and triple notched-band is presented. The designed antenna composed of two orthogonally placed monopole elements, coplanar ground and double Y-shaped branch. The defected substrate structure is used to achieve miniaturization. By slotting successively C-shaped slot, semi-circular slot and rectangular slot on the radiation patch and the ground, achieved three notched bands at 3.5 GHz WiMAX, 5.25 GHz WLAN, and 7.5 GHz X-band. The proposed antenna can operate in range of 2.56-12 GHz with triple notched bands of 3.31-3.96 GHz, 4.58-5.67 GHz and 6.57-8.16 GHz. Considering all the results, it can be concluded that the antenna presented has a great performance in terms of good radiation, high isolation (>24 dB), a low level ECC (<0.01) and a high DG level (>9.99), which proves the presented antenna has good prospect in UWB-MIMO systems.

Modified pentagonal fractal antenna for ultra-wideband applications in communication systems

ABSTRACT Due to the recent expansion in the generations of the communications systems, it is utmost priority to transmit a large amount of data over a wideband frequency spectrum. For this single ultra-wideband (UWB) antennas are the prime choice as compared to the multiple narrow band antennas. A modified pentagonal fractal patch antenna with a modified ground plane covering ultra-wideband has been proposed. The antenna has a compact size of 25 mm × 25 mm × 1.6 mm with peak gain of 2.2 dB. The UWB coverage of the design is achieved by implementing modified co-planar ground, modified fractal geometry and coplanar feed. The proposed design possesses the significant resonance and radiation performance with very compact size on low-cost substrate while covering the whole UWB. Finally, the simulated resonating and radiation characteristics have been validated with the measured characteristics of the fabricated prototype and the results are quite promising.

Frequency Switchable Global RFID Tag Antennae with Metal Compatibility for Worldwide Vehicle Transportation.

This paper presents an effective way to design an RFID tag antenna to operate at three different frequencies by incorporating a switching technique. PIN diode has been used to switch the RF frequency because of its good efficiency and simplicity. The conventional dipole-based RFID tag has been improvised with added co-planar ground and PIN diode. The layout of the antenna is designed with a size of 0.083 λ0 × 0.094 λ0 at UHF (80-960) MHz, where λ0 is the free-space wavelength corresponding to the mid-point of the targeted UHF range. The RFID microchip is connected to the modified ground and dipole structures. Bending and meandering techniques on the dipole length help to match the complex chip impedance with the dipole impedance. Additionally, it scales down the total structure of the antenna. Two PIN diodes are placed along the dipole length at appropriate distances with proper biasing. The ON-OFF switching states of the PIN diodes enable the RFID tag antenna to switch over the frequency ranges (840-845) MHz (India), 902-928 MHz (North America), and 950-955 MHz (Japan).

Nematicity and fractional magnetization plateaus induced by spin-lattice coupling in the classical kagome-lattice Heisenberg antiferromagnet

We investigate the effect of spin-lattice coupling (SLC) on the magnetic properties of the classical kagome-lattice Heisenberg antiferromagnet (KHAF) using improved Monte Carlo updates. The lattice modes are represented by Einstein site phonons, which introduce effective further-neighbor spin interactions in addition to the nearest-neighbor biquadratic interactions. In the weak SLC, the macroscopically degenerate coplanar ground state remains at zero field, while a $\sqrt{3} \times \sqrt{3}$ ordered phase accompanied by a 1/3-magnetization plateau appears in external magnetic fields. In the strong SLC, we find a nematic order at zero field and a 1/9-magnetization plateau associated with a $3 \times 3$ collinear order. Near the phase transition between the 1/9- and 1/3-plateau states, the ergodicity in the single spin flip is practically broken, and slow dynamics appear. We propose that relevant KHAFs with strong SLC would be realized in spinel-based materials.

A dual-band CPW-fed miniature planar antenna for S-, C-, WiMAX, WLAN, UWB, and X-band applications

A miniature planar antenna is a vital component of any portable wireless communication device. The antenna in portable devices should provide wide/multiple operating bands to cover a good number of narrowband services as a multi-band antenna not only reduces the number of antennas but also lessens the system complexity, cost, and device size. To operate over S-, C-, WiMAX, WLAN, UWB, and X-communication bands, in this paper, a dual-band CPW-fed antenna is presented. The anticipated antenna is made up of a vertical bow-tie-shaped patch and two asymmetric ground planes and etched on the same side of the single-sided standard substrate material. To generate two distinct operating bands, an inverted L-shaped parasitic element is inserted within the modified U-shaped coplanar ground plane. The antenna achieved dual operating bands of 3.24–8.29 GHz and 9.12–11.25 GHz in measurement which helps the proposed antenna to cover S-, C-, WiMAX, WLAN, 4G LTE, 5G sub-6 GHz, UWB, and X-communication bands. In the two operating bands, the antenna realized a peak gain of 4.33 dBi, and 4.80 dBi, the maximum radiation efficiency of 86.6%, and 72.6%, and exhibits symmetric radiation patterns. In the operating bands, the antenna also exhibits good time-domain behavior which helps it to transmit the signal with minimum distortion.

Berry phase in the rigid rotor: Emergent physics of odd antiferromagnets

The rigid rotor is a classic problem in quantum mechanics, describing the dynamics of a rigid body with its center of mass held fixed. It is well known to describe the rotational spectra of molecules. The configuration space of this problem is SO(3), the space of all rotations in three dimensions. This is a topological space with two types of closed loops: trivial loops that can be adiabatically shrunk to a point and nontrivial loops that cannot. In the traditional formulation of the problem, stationary states are periodic over both types of closed loops. However, periodicity conditions may change if Berry phases are introduced. We argue that time-reversal symmetry allows for only one new possibility---a Berry phase of $\ensuremath{\pi}$ attached to all nontrivial loops. We derive the corresponding stationary states by exploiting the connection between SO(3) and SU(2) spaces. The solutions are antiperiodic over any nontrivial loop; i.e., stationary states reverse sign under a $2\ensuremath{\pi}$ rotation about any axis. Remarkably, this framework is realized in the low-energy physics of certain quantum magnets. The magnets must satisfy the following conditions: (a) the classical ground states are unpolarized, carrying no net magnetization, (b) the set of classical ground states is indexed by SO(3), and (c) the product $N\ifmmode\times\else\texttimes\fi{}S$ is a half-integer, where $N$ is the number of spins and $S$ is the spin quantum number. We demonstrate this result in a family of Heisenberg antiferromagnets defined on polygons with an odd number of vertices. At each vertex, we have a spin-$S$ moment that is coupled to its nearest neighbors. In the classical limit, these magnets have coplanar ground states. Their quantum spectra, at low energies, correspond to ``spherical top'' and ``symmetric top'' rigid rotors. For integer values of $S$, we recover traditional rigid-rotor spectra. With half-integer $S$, we obtain rotor spectra with a Berry phase of $\ensuremath{\pi}$.

Printed monopole antenna design with CPW fed for ultra wideband application

A circular monopole antenna fed by co-planar waveguide(CPW) for ultra wideband application is described in this article. The usage of a co-planar ground plane help to increase bandwidth for a frequency range 5G frequency spectrum’s mid band. The proposed antenna is designed to operate from 4.8GHz to 14.10GHz. With this proposed antenna, a suitable omnidirectional radiation pattern can be created. Comparison of fractional bandwidth value for various gap between the ground plane and the patch for satisfying the criteria for UWB has been analysed here.

Design and Characterization of 10-Elements MIMO Antenna With Improved Isolation and Radiation Characteristics for mm-Wave 5G Applications

A ten-elements MIMO antenna with improved isolation and reduction of X-polar radiation (XPR) in millimeter (mm) wave region is presented. The individual antenna element consists of stub loaded coplanar waveguide (CPW) structure with elliptical shaped radiator. Defected ground structure (DGS) has been incorporated by engraving partial elliptical shaped slots at the coplanar ground to reduce the mutual coupling effect between the adjacent antenna pairs of the MIMO. The backside of the substrate has a metallic plane with defects which is not connected to the coplanar ground of the antenna. This defected metal structure (DMS) acts as a reflector to improve the radiation characteristics by lowering of XPR as well as improving the co-pol to X-pol isolation. The proposed MIMO structure has a fractional bandwidth of 23.52% (22.5GHz-28.5 GHz) which entails the mm-wave 5G frequency spectrum n258 (24.25-27.5 GHz). The isolation| characteristics of the proposed MIMO antenna are below -35 dB over the operating bandwidth for any pair of adjacent antenna elements which imply significantly improved isolation between the adjacent antenna elements with highly compact layout area of 3.4λ × 8.5λ, where λ is wavelength corresponding to the mid-point of the bandwidth. The inter-element spacing of the MIMO structure is 0.44 λ. The main attractive feature offered by this structure is reduction of XPR in the operating frequency range thus improving the co-pol to X-pol isolation up to 20 dB and 28 dB in the boresight direction in both the XZ and YZ planes respectively. Furthermore, the co-pol to X-pol isolation is maintained above 15 dB almost throughout the elevation angular region -180° to 180° thereby negating the hindrance imposed by surface waves in mm-wave region. The diversity performances in terms of Envelope Correlation Coefficient (ECC), Diversity Gain (DG) and Channel Capacity Loss (CCL) are obtained as 0.1 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup> , 10 dB and 0.005 bps/Hz respectively which are within the acceptable limits. Mean effective gain (MEG) values with respect to the excited port 2 and port 3 is identical and approximately -3dB thus indicating the mean value of these two ports to be almost 1 dB. The multiplexing efficiency of the proposed MIMO antenna is satisfactory over the bandwidth. The group delay is investigated and found to be almost constant with a variation of 1.2 ns thus indicating linear phase characteristic of the antenna. The proposed structure is compared with other mm-wave MIMO antennas and found to be advantageous with respect to the number of antenna elements, compactness, low mutual coupling, co-pol to X-pol isolation, and ECC. A prototype of the proposed 10-elements MIMO is fabricated, and the measured results resemble with the simulated results.

Double Overt-Leaf Shaped CPW-Fed Four Port UWB MIMO Antenna

This paper presents a 4 × 4 multi-input multi-output antenna array for ultra-wideband applications. The single element of the array is comprised of a modified co-planar waveguide-fed double overt-leaf shaped patch radiator. The co-planar ground is optimized to achieve maximum impedance matching in the operating frequency band. The results show that the single antenna element offers an impedance bandwidth of 13.2 GHz starting from 3.2 GHz to 16.7 GHz. It is also observed from the results that the antenna offers good radiation characteristics and acceptable gain for the frequency band of interest. Furthermore, a 4 × 4 MIMO array is designed by utilizing the polarization diversity technique. To improve the isolation performance among antenna elements, a fan-shaped decoupler is introduced on the other side of the substrate, which ensures minimum isolation of 20 dB. Moreover, the proposed MIMO array operates in the frequency range of 2.75–16.05 GHz. The proposed MIMO array is fabricated and measured for the validation of simulation results, and it is observed that both the results are well in agreement.

A dual-band miniature uniplanar antenna on epoxy reinforced woven glass material for WiMAX, WLAN, UWB, and X-band applications

In this paper, a dual-band miniature uniplanar antenna is presented. The antenna size is 24.5 mm × 20 mm × 1.6 mm which consists of a modified bow-tie-shaped radiator, an inverted L-shaped ground plane, and an extended inverted U-shaped ground plane, and designed on the single side of a low-cost epoxy matrix reinforced woven glass material with permittivity 4.6. The numerical results confirm that the radiator is effectively coupled with the coplanar ground planes and the investigated antenna can cover dual frequency bands ranging from 3.32 to 10.9 GHz, and 11.88 to 17.77 GHz. The measured results of the prototype in frequency-domain and time-domain are obtained and compared with the simulated results. The results indicate that the proposed antenna demonstrates good performance over the dual impedance bands, which makes it a very potential candidate for WiMAX, WLAN, UWB, X-band, and Ku-band wireless communication applications.

A Planar Printed Four-Element Pattern Diversity MIMO Antenna Based on Novel Quasi-Yagi Elements

In this paper, a new planar printed quasi-Yagi antenna with compact size and wide bandwidth is presented for a multiple-input-multiple-output (MIMO) antenna system. Antenna element consists of a rectangular driven monopole, a strip director, and a coplanar ground shorted reflector. A planar rectangular monopole is used for the first time as a driven element instead of a dipole to avoid the implementation complexity of BALUN as it can be fed directly by an unbalanced coaxial feed. It has been shown that the antenna element has an impedance bandwidth (|S 11| < −10 dB) of 60.5% ranging from 1.59 to 2.97 GHz. Based on this element, a four-element pattern diversity MIMO antenna is proposed. By utilizing the ground of one element as a reflector for the successive element, a compact size of 109 mm × 109 mm (0.54λ 0 × 0.54λ 0 at 1.5 GHz) has been obtained. Measured bandwidth of 65.9% (1.5–2.97 GHz) with minimum isolation of 13 dB has been achieved. The measured directional patterns and an average gain of 4 dBi, remain stable in the operating band with cross-polarization levels less than −25 dB. The envelope correlation coefficient and channel capacity loss show good diversity performance.

Design and Analysis of Co-planar Waveguide Fed Circular Monopole Antenna for Ultra Wideband Application

A Printed monopole antenna with coplanar waveguide (CPW)- fed having circular shape patch to met the Ultra Wideband technology whose bandwidth is greater than 500MHz is proposed in this article. To enhance the bandwidth co-planar ground plane plays a great role for a frequency band which belong to mid band for 5G frequency spectrum. A good radiation pattern which is usually in 8shape can be achieved with this proposed antenna.

An improved analytical model for broadside coupled transmission line used on planar circuit

Broadside coupled transmission lines have the advantage of more compact size and higher coupling factor compared to the traditional coupled microstrips in the realization of planar circuits such as substrate integrated baluns, directional couplers, and filters on printed circuit boards. A broadside coupled transmission line is a structure with interesting properties composed of two signal lines with strong coupling placed on the top and bottom of a dielectric substrate, surrounded by coplanar ground. This configuration allows the realization of the practical circuit with several hundred ohms impedance for even mode excitation, with the help of lower even mode capacitance. This leads to a high coupling factor and benefits to a high impedance transformation ratio balun or a wide bandwidth filter design. In this paper, an analytical model describing the symmetrical pair of conductors for broadside coupled transmission lines is presented. The analytical model based on the physical geometries of the coupled lines is verified by electromagnetic (EM) simulations and measurements. The results are in very good agreement with each other.

An Asymmetric Meandered Line Based Dual-Band ENG-TL Antenna Loaded with Complementary Closed Ring Resonators for Gain Enhancement

In this article, an asymmetric coplanar waveguide (CPW)-fed dual-band ENG-TL antenna with gain enhancement using complementary closed ring resonators (CCRRs) has been designed and validated. The proposed antenna consists of an asymmetric rectangular patch, meandered line inductor, coplanar ground planes, square-shaped CCRRs, and a radial stub. Simulated results show that the proposed antenna offer triple-band characteristics at 1.28 GHz (1.26–1.29 GHz), 2.61 GHz (2.57–2.65 GHz), and 4.3 GHz (4.15–4.49 GHz). However, the third band has been found as weak resonance and consequently not shown in the paper. Measured results show that the proposed antenna exhibits proper dual-band characteristics covering frequencies 1.18–1.29 GHz (centered at 1.24 GHz) and 2.40–2.68 GHz (centered at 2.56 GHz). Considering fZOR = 1.24 GHz, presented antenna has an electrical size of 0.103 λ 0 × 0.093 λ 0 × 0.0066 λ 0. The proposed antenna has a simulated gain of 1.5 and 2.01 dB at 1.28 and 2.61 GHz, respectively, in the direction of maximum radiation. Above reflection and far-field characteristics makes this antenna suitable for aeronautical radio-navigation (960–1215 MHz), space to earth radio-navigational satellite (1215–1240 MHz) communications. Moreover, the antenna can be potentially built-in smartphones for LTE (2.5–2.69 GHz), WLAN (2.4–2.484 GHz), and WiMAX (2.5–2.69 GHz) applications where gain requirement is reasonable.

DEFECTED GROUND COPLANAR MULTI-BAND-PASS MICROSTRIP FILTER

This paper presents a combination of an inductive coupling technique and coplanar ground plane microstrip filter. Here, inductive coupling technique is used to overcome the unwanted radiation loss generated by the gap between the co-planar ground plane and the transmission line which improves filter characteristics. A defected ground structure (DGS) is integrated with the proposed filter to achieve a tri-bandpass characteristic (1.85, 3.53, and 5 GHz) without hampering the filter performance. The experimental results of the proposed filter are found in good agreement with simulated results.

Truncated elliptical Self-Complementary antenna with Quad-Band notches for SWB MIMO systems

In this work, a compact four-element super-wideband (SWB) multiple-input-multiple-output (MIMO) antenna with four notched bands is designed. The unit resonating element of the MIMO antenna consists of a semi-elliptical monopole patch with high eccentricity. The elliptical patch of the antenna element is truncated from the top to develop a polarization diversity-based compact MIMO configuration. In the coplanar ground surface, a flipped-slot of matched geometry is introduced, which complements the truncated antenna element. Also, four slit-resonators are introduced in the radiating patch of the antenna element to eliminate Wi-Fi, WLAN, Wi-MAX, and X-band signals (2.4, 3.5, 5.5, and 8.5 GHz, respectively) from the SWB. In the proposed quad-port SWB-MIMO configuration, the truncated elliptical self-complementary antenna (TESCA) elements are arranged in rotational symmetry and mutually orthogonal to each other. The diversity antenna exhibits impedance bandwidth (for |S11| < −10 dB) from 1.15 to 40 GHz (bandwidth ratio ~35:1), inter-element isolation greater than 18 dB, and ECC < 0.005. The proposed four-element diversity antenna may be a good candidate for cognitive radio and ubiquitous applications.

CPW-Fed Super-Wideband Antenna With Modified Vertical Bow-Tie-Shaped Patch for Wireless Sensor Networks

In this paper a coplanar waveguide-fed super-wideband antenna is presented for wireless sensor networks. The studied low-profile design is comprised of a modified bow-tie-shaped vertical patch and two asymmetrical ground planes and has been prototyped on a single-sided FR4 microwave substrate. The anticipated antenna has an overall size of $0.25\lambda \times 0.20\lambda $ at 3.035 GHz, the lowest frequency of the operating band. The vertical radiator coupled well with the two coplanar ground planes which enabled the studied antenna to achieve an operating band of 3.035–17.39 GHz (140.56%). The presented antenna demonstrates almost omnidirectional radiation patterns over the entire operating with an average gain of 4.56 dBi and average efficiency of 76.62%. The antenna also features with high fidelity factor, flat group delay, small phase distortion, and good response of transfer function. All these characteristics of the studied antenna make it a robust contender for wireless sensor node applications.

A broadband circularly polarized monopole antenna for millimeter‐wave short range 5G wireless communication

This article describe the design and measurement of a broadband circularly polarized (CP) monopole antenna for millimeter wave short range 5G Wireless communication applications. This antenna is comprised of a T-shaped monopole antenna with an inverted-L grounded stub and an asymmetric coplanar wave guide feed. To attain the broadband CP, an inverted-L grounded stub is embedded in the coplanar ground and introducing asymmetry in the horizontal T-shaped patch connected feed line monopole antenna. A compact size of 1.877λL × 1.706λL × 0.130λL is accomplished when measured at lower edge frequency (fL,|S11|). For the proposed antenna structure conforming to fL,|S11|, a measured 3-dB axial ratio bandwidth of 13.67% (4 GHz, 27.26-31.26 GHz), impedance bandwidth of 27.9% (8.3 GHz, 25.6-33.9 GHz), peak gain of 7.15dBi, and a bidirectional patterns with a dual sense polarization are attained.

Reconfigurable hexagon shaped printed antenna for cognitive radio application

The article presents a new reconfigurable antenna suitable for cognitive radio (CR) application under interweave paradigm. The new sleeve-like geometry is improvised in the antenna for designing broadband sensing antenna and it consists of a hexagon shaped metallic patch along with modified coplanar ground plane structure and feed line (nonconventional coplanar waveguide feed). The p-i-n diodes are also incorporated with the printed antenna. By varying the switching states of the diodes, frequency hopping occurs over the frequency range 3.75 to 12.67 GHz (108.64% BW) which is better compared to the existing sensing antennas used for designing CR antenna. The antenna also offers suitable gain and omnidirectional radiation pattern over the operating range of frequencies. In addition to frequency domain analysis, time-domain synthesis of the proposed antenna is also executed by using well-known electromagnetic solver CST software. Moreover, the antenna is fabricated and measured parameters are in good accordance with measured results.