Syed Idris Syed Hassan

Development of a New Approach for High-Quality Quadrupling Frequency Optical Millimeter-Wave Signal Generation Without Optical Filter

In this paper, we propose a new approach to generate quadrupling-frequency optical millimeter-wave (mm-wave) signal with carrier suppression by using two parallel Mach-Zehnder modulators (MZMs) in Radio-over-flber (RoF) system. Among the numerous properties of this approach, the most important is that a fllterless optical mm-wave at 60GHz with an optical sideband suppression ratio (OSSR) as high as 40dB can be obtained when the extinction ratio of the MZM is 25dB. Simplicity and cost-efiectiveness have made this approach a compelling candidate for future wave-division-multiplexing RoF systems. Theoretical analysis is conducted to suppress the undesired optical sidebands for the high-quality generation of frequency quadrupling mm-wave signal. The simulation results show that a 60GHz mm-wave is generated from a 15GHz radio frequency (RF) oscillator with an OSSR as high as 40dB and an radio frequency spurious suppression ratio (RFSSR) exceeding 35dB without any optical or electrical fllter when the extinction ratio of the MZM is 25dB. Furthermore, the efiect of the non-ideal RF-driven voltage as well as the phase difierence of RF-driven signals applied to the two MZMs on OSSR and RFSSR is discussed and analyzed. Finally, we

A 2.45 GHz circular patch antenna with harmonic suppression for wireless power transmission

This paper proposed a new circular patch antenna design with harmonics suppression capability. The purpose of harmonic suppression antenna is to eliminate the use of harmonic filter circuit in rectenna circuit. By introducing slits at the antenna patch and stub at the transmission line, unwanted harmonics frequencies are successfully suppressed. In addition, the size of proposed circular patch antenna is reduced by using partial ground and circular slot technique at the ground plane. The patch antenna is design on FR4 substrate with εr=4.7 and a thickness of 1.6 mm has −48dB return loss at 2.45GHz and suppress the second and third harmonic up to −3dB. The proposed harmonic suppression antenna can be applied in rectenna and active integrated antenna (AIA) applications, thus the circuit become compact, cheaper and more efficient.

A 2.45 GHz harmonic suppression rectangular patch antenna

This paper presented a new design of rectangular patch antenna which is able to suppress the harmonic frequencies. The techniques that are used in the suppression of harmonics are a notch-loaded and curvature slots at the antenna patch together with an open stub and inset feed transmission line. The partially ground with a circular slot at ground plane is also introduced to reduce the overall patch size. The patch antenna is designed on an FR4 substrate with εr=4.7 and a thickness of 1.6 mm give -40dB return loss at 2.45GHz and suppress all the harmonics up to -1dB. The proposed of harmonic suppression antenna can avoid by using harmonic filter circuit in the rectenna circuit and active integrated antenna (AIA) applications, thus the system becomes compact and cheaper.

Comparison between Parameter of Single Core Unarmoured Aluminium Conductor 6.35/11 kV Underground Cable for Partial Discharge Measurement Using EMTP-ATP Software

Partial Discharge (PD) is one of a symptom in the underground cable before the fault happens.This paper concerned with estimation and detection problems related to PD phenomena in buried underground cables. The Rogowski coil has been implemented to analyze this symptom. The various sizes of nominal cross-sectional area cross-linked polyethylene (XLPE) cable with 6.35/11 KV single core unarmored aluminum conductors that follows Nexans manufacturer datasheet based on design standard IEC 60502 has been used in the simulation using Electromagnetic Transient Program-Alternative Transient Program (EMTP-ATP) software. The Lumped parameter is used for the Rogowski coil sensor model. Meanwhile, for Double-end measurement using J-Marti model is designed to evaluate the parameter changing in the measurement.Based on the measurement, the value of amplitude voltage and current is proportional increase depends on the size of cross-sectional area of conductor XLPE cable.

An investigation of ambient radio frequency as a candidate for energy harvesting source

In this paper, a feasibility study of the ambient radio frequency (RF) as an energy source to be harvested and converted into electrical energy is presented. This study is to investigate the ability to harvest the ambient RF power density produced by the GSM telecommunication tower for very low power device usage. To capture the RF signal, a normal mode helical rectenna is designed and fabricated. The reason of choosing the normal mode helical antenna in this study is to solve the major problem of a microstrip patch antenna array where the overall size is very large. Experimental results showed that with -10dBm input power, a voltage of 0.3V is generated at the distance 2.5 meters. Hence, this proved that the ambient RF energy can be a suitable candidate as an energy harvesting source.

Effect of unshielded and shielded Rogowski coil sensor performance for partial discharge measurement

This paper presents the analysis of constructed shielded Rogowski coil (RC) sensor for partial discharge (PD) measurement. The RC sensor with rectangular shape has been designed in order to compare the performance unshielded and shielded type in term of sensitivity. Solidwork 3D CAD software has been used to design the core of RC sensor with their casing. Marker Board Replicator 2X 3D printer is used to print the design. An experiment has been conducted to evaluate the difference performance of unshielded and shielded RC sensor with amplitude range PD signal between 1 V to 5 V respectively and the frequency is fixed to 1 MHz. The difference terminating resistance has been installed to the RC sensor too. From the experiment, the percentage average losses of unshielded and shielded RC sensor from 1 V to 5 V at 14.48 % is achieved. The low level of PD signal is challenging to be detected by the RC sensor. The terminating resistance of the coil is a part of parameter which can improve the performance of RC sensor.

Three-Point Technique for Partial Discharge Location on XLPE Armoured Underground Cable

Recently, a new partial discharge location technique called three-point technique had been introduced to locate partial discharge on underground cable. It is the improvement of double-end technique. In this paper, the mathematical formula of three-point technique had been simplified from previous research. Alternative Transient Program (ATP) was being used to simulate both double-end and three-point technique. The results of the simulation were compared and analysed based on the accuracy, cost of implementation and algorithm complexity of the technique. Three-point technique had shown significant improvement in the accuracy of partial discharge location on underground cable.

Harmonics suppression circular polarization elliptical shape microstrip patch antenna

This paper proposed a new design of a 2.45 GHz harmonic suppression circularly polarized microstrip patch antenna. The purpose of harmonic suppression antenna is to eliminate the using of harmonic filter circuit in a rectenna system as well as for the others active integrated antenna (AIA) applications. By introducing a defected ground structure (DGS) technique with a back-to-back U shape slot, the magnitude of the return loss at the harmonic frequencies are suppressed successfully. The patch antenna is designed on an FR4 substrate with εr=4.7 and a thickness of 1.6 mm have -28dB return loss at 2.45GHz and suppress the second and third harmonic up to -0.8dB and -1.8dB respectively.

A study in OCS millimeter-wave generation using two parallel DD-MZMs

This study highlights a particular form of optical millimeter-wave (MMW) generation by using a dual-drive Mach-Zehnder Modulator (DD-MZM) and demonstrates a new method to generate an optical carrier suppression (OCS) MMW signal with frequency quadrupling of the local oscillator via two parallel DD-MZMs based on this form. Theoretical derived equations and numerical simulation verified that two strong optical sidebands, centered at the optical carrier and separated by four-fold the RF drive frequency can be generated when the extinction ratio (ER) of the DD-MZMs is 30 dB.

Optical generation of 60-GHz signal for millimeter wave wireless communication

In this paper, a quadruple-frequency optical millimeter-wave (mmW) signal generation using an integrated dual-parallel MZM (IDP-MZM) is presented. With properly adjusting the phase delay, biasing, and modulation index, an optical mmW signal at 60-GHz with an Optical Sideband Suppression Ratio (OSSR) up to 28 dB is obtained through simulation. The Radio Frequency Spurious Suppression Ratio (RFSSRR) is 32.2 dB. Furthermore, the impact of non-ideal MZM on RFSSRR is studied through simulation. Although a large modulation index is utilised to achieve frequency quadrupling, the simplicity and high quality have made this scheme a viable solution for mmW wireless communication networks.