M. Samsuzzaman

A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications

A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR) and capacitance-loaded strip (CLS) unit cells is presented for Ultra wideband (UWB) microwave imaging applications. Four left-handed (LH) metamaterial (MTM) unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR) with a capacitance-loaded strip (CLS) to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm3, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4–12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications.

A Negative Index Metamaterial-Inspired UWB Antenna with an Integration of Complementary SRR and CLS Unit Cells for Microwave Imaging Sensor Applications.

This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator) and CLS (capacitive loaded strip) unit cells for microwave imaging sensor applications. This metamaterial UWB antenna sensor consists of four unit cells along one axis, where each unit cell incorporates a complementary SRR and CLS pair. This integration enables a design layout that allows both a negative value of permittivity and a negative value of permeability simultaneous, resulting in a durable negative index to enhance the antenna sensor performance for microwave imaging sensor applications. The proposed MTM antenna sensor was designed and fabricated on an FR4 substrate having a thickness of 1.6 mm and a dielectric constant of 4.6. The electrical dimensions of this antenna sensor are 0.20 λ × 0.29 λ at a lower frequency of 3.1 GHz. This antenna sensor achieves a 131.5% bandwidth (VSWR < 2) covering the frequency bands from 3.1 GHz to more than 15 GHz with a maximum gain of 6.57 dBi. High fidelity factor and gain, smooth surface-current distribution and nearly omni-directional radiation patterns with low cross-polarization confirm that the proposed negative index UWB antenna is a promising entrant in the field of microwave imaging sensors.

Printed Wide-Slot Antenna Design with Bandwidth and Gain Enhancement on Low-Cost Substrate

This paper presents a printed wide-slot antenna design and prototyping on available low-cost polymer resin composite material fed by a microstrip line with a rotated square slot for bandwidth enhancement and defected ground structure for gain enhancement. An I-shaped microstrip line is used to excite the square slot. The rotated square slot is embedded in the middle of the ground plane, and its diagonal points are implanted in the middle of the strip line and ground plane. To increase the gain, four L-shaped slots are etched in the ground plane. The measured results show that the proposed structure retains a wide impedance bandwidth of 88.07%, which is 20% better than the reference antenna. The average gain is also increased, which is about 4.17 dBi with a stable radiation pattern in the entire operating band. Moreover, radiation efficiency, input impedance, current distribution, axial ratio, and parametric studies of S11 for different design parameters are also investigated using the finite element method-based simulation software HFSS.

Microwave Imaging Sensor Using Compact Metamaterial UWB Antenna with a High Correlation Factor

The design of a compact metamaterial ultra-wideband (UWB) antenna with a goal towards application in microwave imaging systems for detecting unwanted cells in human tissue, such as in cases of breast cancer, heart failure and brain stroke detection is proposed. This proposed UWB antenna is made of four metamaterial unit cells, where each cell is an integration of a modified split ring resonator (SRR), capacitive loaded strip (CLS) and wire, to attain a design layout that simultaneously exhibits both a negative magnetic permeability and a negative electrical permittivity. This design results in an astonishing negative refractive index that enables amplification of the radiated power of this reported antenna, and therefore, high antenna performance. A low-cost FR4 substrate material is used to design and print this reported antenna, and has the following characteristics: thickness of 1.6 mm, relative permeability of one, relative permittivity of 4.60 and loss tangent of 0.02. The overall antenna size is 19.36 mm × 27.72 mm × 1.6 mm where the electrical dimension is 0.20 λ × 0.28 λ × 0.016 λ at the 3.05 GHz lower frequency band. Voltage Standing Wave Ratio (VSWR) measurements have illustrated that this antenna exhibits an impedance bandwidth from 3.05 GHz to more than 15 GHz for VSWR < 2 with an average gain of 4.38 dBi throughout the operating frequency band. The simulations (both HFSS and computer simulation technology (CST)) and the measurements are in high agreement. A high correlation factor and the capability of detecting tumour simulants confirm that this reported UWB antenna can be used as an imaging sensor.

Inverted S-shaped compact antenna for X-band applications.

A novel probe-fed compact inverted S-shaped multifrequency patch antenna is designed. By employing two rectangular slots that change the conventional rectangular patch into an inverted S-shaped patch, the antenna is able to operate in triple frequency in the X-band. The performance criteria of the proposed design have been experimentally verified by fabricating a printed prototype. The measured results show that the −10 dB impedance bandwidth of the proposed antenna at lower band is 5.02% (8.69–9.14 GHz), at middle band is 9.13% (10.47–11.48 GHz), and at upper band is 3.79% (11.53–11.98 GHz). Two elliptical slots are introduced in the ground plane to increase the peak gain. The antenna is excited by a simple probe feeding mechanism. The overall antenna dimension is  0.52λ × 0.60λ × 0.046λ at a lower resonance frequency of 9.08 GHz. The antenna configuration and parametric investigation are conducted with the help of the high frequency structural simulator, and a good agreement is achieved between the simulated and measured data. The stable gain, omnidirectional radiation pattern, and consistent radiation efficiency in the achieved operating band make the proposed antenna a suitable candidate for X-band applications.

Dual elliptical patch antenna design on low cost epoxy resin polymer substrate material

A new dual elliptical patch antenna is proposed for wideband wireless application. The proposed antenna achieved wideband using internal and external parasitic radiators. The microstrip transmission line fed antenna is consisted of two elliptical radiating patches with two external annular parasitic elements and a partial ground plane. The proposed antenna is printed on epoxy resin reinforced woven glass dielectric material. The antenna structure is planar, and its design is simple and easy to fabricate. Experimental result shows that the designed antenna has achieved an impedance bandwidth of 7.28 GHz (VSWR 2) from 5.72 GHz to 13.0 GHz. Moreover, the antenna shows good radiation efficiency with accacptable radiation patterns within the operating frequency band.

Circularly polarized high gain S band antenna for nanosatellite

A circular polarized highly directional S band patch antenna for small satellite applications has been proposed in this invention. The proposed antenna comprises of a square ground plane and two circular radiating patches with annular circular slot fed by a coaxial probe. The circular slot in the radiating patch is responsible for creating resonance at the S band. The prototype is can be easily integrated with a small satellite due to the simplicity of the design. The modification of the circular shape patch by cutting circular shape slots help to excite the resonance at the desired frequency. The simulation and the experimental results have a good agreement. The proposed antenna has achieved an impedance bandwidth of 55 MHz (2.380 GHz-2.435 GHz) and axial ratio (AR) < 3 dB is about 35 MHz (2.410 MHz-2.445 MHz) in the operating band. The prototype has achieved a gain of 8.13 dBi at centre frequency of 2.42 GHz. The directional radiation pattern, circular polarization (CP), and high gain characteristics make the proposed antenna suitable for small satellite applications.

Circularly Polarized S Band Dual Frequency Square Patch Antenna Using Glass Microfiber Reinforced PTFE Composite

Circularly polarized (CP) dual frequency cross-shaped slotted patch antenna on 1.575 mm thick glass microfiber reinforced polytetrafluoroethylene (PTFE) composite material substrate is designed and fabricated for satellite applications. Asymmetric cross-shaped slots are embedded in the middle of the square patch for CP radiation and four hexagonal slots are etched on the four sides of the square patch for desired dual frequency. Different substrate materials have been analysed to achieve the desired operating band. The experimental results show that the impedance bandwidth is approximately 30 MHz (2.16 GHz to 2.19 GHz) for lower band and 40 MHz (3.29 GHz to 3.33 GHz) for higher band with an average peak gain of 6.59 dBiC and 5.52 dBiC, respectively. Several optimizations are performed to obtain the values of the antenna physical parameters. Moreover, the proposed antenna possesses compactness, light weight, simplicity, low cost, and circularly polarized. It is an attractive candidate for dual band satellite antennas where lower band can be used for uplink and upper band can be used for downlink.

Dual wideband n shaped patch antenna loaded with shorting pin for wireless applications

In this paper, a compact N shaped dual band patch antenna loaded by shorting pin is designed. The lessening in patch size is achieved by perturbing the surface current path on the edge of a circular patch antenna by two triangular slots which make the patch as N shaped. Dual wideband is achieved by combining two triangular slots and shorting pin. Simulated results which are carried out by Finite Element Method (FEM) based simulator HFSS such as antenna impedance bandwidth, input impedance and radiation characteristics have been presented and discussed. The lower impedance bandwidth 1.46 GHz covers from 2.89 GHz to 4.35 GHz and the upper impedance bandwidth 2.17 GHz covers from 7.69 GHz to 9.86 GHz. The overall dimension of the antenna is 13×13×1.575 mm3.

A compact disc-shaped super wideband patch antenna with a structure of parasitic element

In this paper, a disc-shaped monopole antenna has been investigated for super-wideband applications with a structure of parasitic element. The proposed SWB antenna consists of disc-shaped patch and a partial ground plane with a structure of parasitic element. The parasitic element consists of 4 rectangular embedded slots on the ground plane. This parasitic element on the ground plane leads the UWB frequency band into the SWB frequency band. This proposed SWB antenna is fed by a microstrip line and is printed on low dielectric FR4 material of 1.6 mm thickness. All the simulations are performed using commercially available, finite element method (FEM) based Ansoft high-frequency structure simulator (HFSS) software and CST Microwave Studio. Measured results exhibit that the proposed disc-shaped antenna shows a wide bandwidth which covers from 2.90 GHz to more than 20 GHz, with a compact dimension of 25 mm x 33 mm for VSWR = 2062. 22) are a good deal sounder than the existing super wideband antennas which make it appropriate for many wireless communication systems such as L, C, X, UWB, Ku, and SWB bands.