Ultra wideband printed monopole antenna with dual-band circular polarization

An ultra wideband printed monopole antenna with dual band circular polarization for wireless application is presented. The antenna dimensions are 30 × 30 × 1.6 mm3. The proposed antenna is able to cover frequency range between 2.65 GHz and 11 GHz with impedance bandwidth is around 122%. With the use of I-shape slit in the radiation element and the T-slot in the ground plane, the ultra wideband and circular polarization are excited. In addition, the rectangular slit is added in the ground plane, to enhance the impedance- and Axial Ratio - bandwidth. Furthermore, the dual band circular polarization with right hand circular polarization at 3.1 GHz and the left hand circular polarization at 7 GHz are obtained. Also, the 3-dB axial ratio bandwidths are about 242 and 246 MHZ at the lower and upper band without rectangular slit and 356 and 546 MHZ at the lower and upper band with rectangular slit, respectively

A novel green antenna phase-shift system with data acquisition boards

A novel green phase shifter system is proposed in this research. The system is developed by a combination of reconfigurable beam steering antennas and data acquisition (DAQ) boards. A combination of two reconfigurable beam steering antennas, located side-by-side, forms a spatial configuration structure with a fabricated ‘green’ element plank of rice husk placed in between. The concept of a spatial configuration technique has been ‘mutated’ by shifting the structure of spiral feed line and aperture slots of first beam steering antenna by as much as 45 ◦ . The PIN diode switches connected to the DAQ boards enable the intelligent capability of the spatial antennas. The activation of certain degree radiation patterns of either the first beam steering antenna or the second beam steering antenna depends on the memory of the DAQ boards — Beam Manager. When an intruder comes from the cardinal angles of 0◦/ 360◦, 90◦, 180◦, or 270◦, its range and angles’ location will be automatically detected by the first antenna through the output ports of the 1st DAQ: P1.0, P1.1, P1.2, and P1.3. The second antenna is then activated by the output ports of the 2nd DAQ: P2.0 up to P2.3, to adaptively maneuver the beam towards four different ordinal directions of 45◦, 135◦, 225◦, and 315◦

A compact UHF RFID tag antenna for soil monitoring

UHF RFID technology is currently being chosen to replace the existing soil monitoring system for smart agriculture. However, when attached to backing objects, the current RFID tag typically has a large footprint and a short read distance. Therefore, this paper introduces a compact tag antenna design comprising a slotted radiating patch connected to a ground plane via an inductive stub. The tag antenna is mounted on loamy soil for soil monitoring purposes. The proposed tag has a small size of only 48.2 � 48.2 mm, a power transmission coefficient of 0.99, and a longer theoretical read range of 9

A compact UHF RFID tag antenna for soil monitoring

UHF RFID technology is currently being chosen to replace the existing soil monitoring system for smart agriculture. However, when attached to backing objects, the current RFID tag typically has a large footprint and a short read distance. Therefore, this paper introduces a compact tag antenna design comprising a slotted radiating patch connected to a ground plane via an inductive stub. The tag antenna is mounted on loamy soil for soil monitoring purposes. The proposed tag has a small size of only 48.2 � 48.2 mm, a power transmission coefficient of 0.99, and a longer theoretical read range of 9m

A compact UHF RFID tag antenna for soil monitoring

UHF RFID technology is currently being chosen to replace the existing soil monitoring system for smart agriculture. However, when attached to backing objects, the current RFID tag typically has a large footprint and a short read distance. Therefore, this paper introduces a compact tag antenna design comprising a slotted radiating patch connected to a ground plane via an inductive stub. The tag antenna is mounted on loamy soil for soil monitoring purposes. The proposed tag has a small size of only 48.2 � 48.2 mm, a power transmission coefficient of 0.99, and a longer theoretical read range of 9

Wideband Frequency Selective Surface Based Transmitarray Antenna at X-Band

In this paper, a wideband multilayer transmitarray antenna is designed for Ku frequency band. The unit cell is designed at 12GHz using frequency selective surface structure. Double square ring with center patch based multilayer unit cell is simulated. The effect of substrate thickness variation on transmission coefficient magnitude and phase range is discussed. The horn antenna designed at X-band will be used as feed source for transmitarray antenna. Transmitarray simulation results show wide impedance bandwidth from 10 to 13GHz. Wide gain bandwidth of 1.975GHz with peak gain of 18.96dB is achieved. The proposed transmitarray design will find applications in high gain, directional, low profile antennas for X-band communication systems

The Investigation of Polarization Diversity in MIMO System at 2.4 GHz

This paper describes the concept of multiple input multiple output (MIMO) system using polarization diversity that can enhance the channel capacity and increased the data output performance of the system. The microstrip antenna array is designed, fabricated and measured at the desired operating frequency for this measurement. Computer Simulation Technology (CST) software is used to design and simulate the microstrip antenna array. The simulation and measurement data results are compared and discussed. The fabricated microstrip antenna is used to develop the Radio Frequency (RF) MIMO test bed system. The system measurement has been conducted in Microwave Laboratory at Faculty of Electronic and Computer Engineering, University Technical Malaysia Melaka at the operating frequency of 2.4 GHz. The spatial diversity and polarization diversity are applied in measurement campaign to investigate the performance of the wireless MIMO channel. The data obtained from the measurement is processed using MATLAB software in order to calculate the MIMO channel capacity. The analysis has been focused on the effect of the MIMO channel capacity due to the proposed measurement setup configurations. The channel capacity is increased from 0.03 b/s/Hz to 0.09 b/s/Hz when polarization diversity is applied at both transmitter and receive

Slot implementation on second iteration of fractal log periodic dipole antenna for uhf band application

In this paper, the design of the second iteration of Log Periodic Fractal Koch Antennas (LPFKA) with and without slot implementation is designed for Ultra High Frequency (UHF) band applications. The slot implementation is applied on each of the radiating elements to reduce the antenna's size and to prevent the shifting of a lower frequency to a higher frequency. The antenna is operated at a frequency between 0.5 GHz and 9.0 GHz. The Computer Simulation Technology (CST) software was used to design and simulate the antenna. The performance of the antenna such as reflection coefficient, radiation pattern and gain have been analyzed. The antennas have been fabricated using an FR4 laminated board with a dielectric constant of 4.6, tangent loss of 0.019, and a thickness of 1.6mm. The results show a positive outcome, with a stable radiation pattern over the operational bandwidth and a reflection coefficient of less than -10 dB for the designed frequency

X-band rectangular to square waveguide transition for transmitarray unit cell characterization

In this paper, a characterization setup for transmitarray unit cell analysis is designed in CST studio using rectangular to square waveguide transition for X-band applications. A wideband transmitarray unit cell is designed using split ring resonator and unit cell simulations show wide impedance matching bandwidth of 43.7%. In this simulation, the waveguide transition length is varied to reduce the reflection coefficient magnitudes below -20dB. Then, the square cross section area of waveguide is made variable and cutoff frequency variation over 4GHz is illustrated. Finally, the model for real time test setup is simulated along with the transmitarray unit cell and the results show high transmission magnitude of -O.23dB. This setup can also be used for other frequency selective surface unit cells characterization

A low-profile compact meander line telemetry antenna with low SAR for medical applications

A low-profile Compact Meander Line Telemetry Antenna (CMLTA) operating at 402.5 MHz for the Medical Implant Communication System (MICS) band medical applications is introduced. The proposed antenna focuses specifically on pacemaker telemetry applications. The meander line technique with an open loop configuration and simple transmission line feeding mechanism has been used for achieving the compact design. Based on the theory of surface current distribution, the proposed technique provides the opportunity to increase the electrical dimensions while decreasing the physical dimensions of the antenna. Further design optimization is carried out to optimize the overall antenna size to a maximum volume of 4080 mm3. By introducing CMLTA, the size of the antenna is reduced by 79% as compared to the previous work. The proposed antenna demonstrated satisfactory performance with 10 dB bandwidth of 6.17%, a maximum gain of -22 dBi and an EIRP of -25.28 dBi. The analysis of Specific Absorption Rate under premise use of 1 W input power provided the maximum 1 g and averaged 10 g SAR of 74.7 W/kg and 17.7 W/kg, respectively, demonstrating a satisfactory level according to the IEEE standard safety guidelines. Fabrication and measurements are carried out where measured results are found to be in good agreement with the simulated results. With the optimized dimensions, satisfactory gain, EIRP, and SAR performance, the proposed CMLTA is deemed suitable for pacemaker telemetry applications for effective communication