Zubaida Yusoff - Academia.edu (original) (raw)

Papers by Zubaida Yusoff

2022 IEEE International RF and Microwave Conference (RFM)

2022 International Symposium on Antennas and Propagation (ISAP)

… (EuMC), 2011 41st …, 2011

... the Novel “Continuous Inverse Class-F Mode” V. Carrubba, AL Clarke, M. Akmal, Z. Yusoff, J. L... more ... the Novel “Continuous Inverse Class-F Mode” V. Carrubba, AL Clarke, M. Akmal, Z. Yusoff, J. Lees, J. Benedikt, SC Cripps, PJ Tasker Center for High Frequency Engineering CardiffUniversity Cardiff, Wales, United Kingdom carrubbav@cardiff.ac.uk ...

Jurnal Teknologi

An all-digital phase locked loop (ADPLL)-based local oscillator (LO) of RF transceiver applicatio... more An all-digital phase locked loop (ADPLL)-based local oscillator (LO) of RF transceiver application such as radio-frequency identification (RFID) system has gained popularity by accessing the benefits in complementary metal-oxide semiconductor (CMOS) process technology. This paper reviews some state-of-art of the ADPLL structures based on their applications and analyses its major implementation block, which is the digital-controlled oscillator (DCO). The DCO is evaluated based on its CMOS scaling and its performance in ADPLL, such as the power consumption, the chip area, the frequency range, the supply voltage, and the phase noise. Based on the review, the reduction in CMOS scaling decreases the transistor size in ADPLL design which leads to a smaller area and a low power dissipation. The combination of the time-to-digital (TDC) and the digital-to-time converter (DTC) that is used as the phase-frequency detector (PFD) in ADPLL is proposed to reduce the power and phase noise performan...

IEEE Access

Beamforming networks for multiple beam antennas are believed to be in the vanguard of technologic... more Beamforming networks for multiple beam antennas are believed to be in the vanguard of technological developments in mmWave for 5G wireless applications. The basic idea of beamforming technique is the application of multiple antenna elements radiating the same signal at an identical phase and wavelength, into one strong signal pointed to a specific direction. For low cost and power consumption, radio frequency beamforming networks (RF-BFNs) such as Blass matrices, Butler matrices, and Nolen matrices will play a critical role in achieving the ever-increasing demands in wireless technology. Therefore, this study aims to present a comprehensive survey and developments of RF-BFNs with (particular focus in Butler matrices). From the fundamental perspectives of the beamforming techniques and progress over time, component evolution includes branch-line coupler (BLC), Phase shifter (PS), and Crossovers to complete system Butler matrix (BM) integration. Different design techniques to improve bandwidth, size reduction, multi-band, and other performance characteristics are discussed extensively. Furthermore, the paper also discusses different geometry of Butler matrices in open microstrip transmission lines, substrate integrated waveguide (SIW) and gap waveguide (GWG) technologies highlighting key developments and research challenges from single band to dual-band operations. We expect this paper to provide more profound insights into the designs processes and suggest suitable ways to facilitate further developments of RF-beamforming networks at mmWave and sub-mmWave frequency ranges. INDEX TERMS Beamforming networks (BFNs), Butler matrix (BM), fifth-generation (5G), metamaterial (MTM), millimetre-waves (mmWave), substrate integrated waveguide (SIW), gap waveguide (GWG), ridge gap waveguide (RGW), groove gap waveguide (GGW).

2019 IEEE Asia-Pacific Conference on Applied Electromagnetics (APACE)

This paper presents a dual layer butler matrix for 5G wireless communication at 28 GHz using via-... more This paper presents a dual layer butler matrix for 5G wireless communication at 28 GHz using via-hole. Via-hole is proposed as the phase shifter connecting dual layer substrate Butler Matrix. In this design, two sides of the substrate are stacked to minimize the occupied area and to eliminate crossover component, resulting in a compact size and a low conductor loss. The two hybrids are designed at the top and bottom substrate with via-holes as the phase shifters and common ground plane at the centre. Phase shifters are designed using via-hole and Butler Matrix strip line is optimized for -45º, +135º, -135º and +45º output phase respectively. Consecutive phase input signal combiner/divider using the proposed Butler Matrix is executed at 28 GHz for fifth generation (5G) wireless connectivity.

2019 IEEE 3rd International Conference on Circuits, Systems and Devices (ICCSD)

This paper examines the application of a broadband modulated measurement system, and specifically... more This paper examines the application of a broadband modulated measurement system, and specifically how such a system can be used in combination with active IF load-pull in order to characterize a device whilst operating in an Auxiliary Envelope Tracking (AET). The AET modifies dynamically the instantaneous DC applied to the device through the optimization of baseband impedance. The experimental measurements are carried out on a GaN HEMTs device to investigate the idea of improving the linearity of the device using the very mechanism that is employed to improve efficiency of the device. The investigations have shown a significant improvement in linearity of the device.

2019 IEEE Regional Symposium on Micro and Nanoelectronics (RSM)

This paper presents the design and simulation of an inverse Class F (F-1) radio frequency power a... more This paper presents the design and simulation of an inverse Class F (F-1) radio frequency power amplifier (RFPA) using a 10W Gallium Nitride (GaN) High Electron Mobility Transistor (HEMT) CGH40010 manufactured by Cree. The simulated device is operated at 1.5 GHz frequency. This paper also discusses the details on the analysis and device-model based simulation design procedure such as the load pull, the source pull, the parasitic de-embedding network, input and output matching design, and the waveform analysis using Keysight Advanced Design System (ADS) software. The simulation results exhibit the maximum drain efficiency (DE) of 73.7% and gain of 18.3 dB at the output power of 40 dBm.

Utilization of Dynamic Spectrum Management (DSM) in V2V communications by selecting an appropriat... more Utilization of Dynamic Spectrum Management (DSM) in V2V communications by selecting an appropriate frequency band through the selection of available licensed and unlicensed frequency bands for vehicles

F1000Research, Dec 23, 2021

Beamforming is a key element of 5G that uses advanced antenna technologies to focus a wireless si... more Beamforming is a key element of 5G that uses advanced antenna technologies to focus a wireless signal to a defined direction. Butler Matrix (BM) as a beamforming network is used to control the beam direction by utilizing the amplitude and the output phase. A particular technique for designing BM is through substrate integrated waveguide (SIW), which is used to realize the bilateral edge wall vias where the waveguide mode propagates through to support the current flow and reduce the loss of surface wave. Unlike conventional BM, the proposed design requires only hybrid couplers and phase shifter without any crossover. In this BM structure, the SIW hybrid coupler is designed, with two phase shifters of-90°, and one phase shifter of-180° to control the amplitude and phase shifting. This results in an optimized transmission amplitude and output phase difference. The BM also circumvents any crossover, to provide minimal losses. The hybrid coupler exhibits Sii and Sij characteristics at 28 GHz, with values of-27.35 dB for return loss,-3.9 dB for insertion loss,-3.2 dB for coupling, and-26.54 dB for the isolation. In the BM design, high transmission efficiency is observed where the return loss is less than-10 dB, while minimal transmission amplitudes are obtained within the values of-6 ± 3 dB. The three-port BM is designed using SIW with minimal loss and the phase difference at each respective output port of the BM shows values of 0°,-120°, and 120°. The three consecutive beams with the gains of 11.1 dBi for port 1 excitation, 9.06 dBi for port 2 excitation and 10.4 dBi for port 3 excitation is achieved when the antenna array is fed to the BM, and each of the radiated beams has beam angles of 0,-27 and 27 degrees. Open Peer Review Approval Status AWAITING PEER REVIEW Any reports and responses or comments on the article can be found at the end of the article.

2019 IEEE 14th Malaysia International Conference on Communication (MICC), 2019

Device to device communication is a vital technology when it comes to the future communication sy... more Device to device communication is a vital technology when it comes to the future communication system. It can increase the sum rate, area coverage and decreases the latency of the network. However, the interference caused by introducing D2D communication can affect the overall performance of the cellular network. In this paper, we proposed a resource allocation algorithm using the fair and restricted assignment for D2D communication. The advantage of our proposed algorithm is that it decreases the total system interference while maintaining the target sum rate. We have divided our algorithm into two parts. Part I, assigns the resources of the cellular user to D2D pair using Hungarian Minimisation and Maximization algorithm(weight bipartite matching) considering two separate cases (fair and restricted assignment). In cases where the system sum rate doesn't satisfy the target sum rate, a single cellular user shares its resources to two different D2D pair (while maintaining the system sum rate). Part II further checks and decreases the interference by using local interference management technique. The results were compared to other existing algorithms like TAFIRA and MIKIRA. The simulation results proves that our algorithm shows superior performance results in terms of minimization of interference and maintaining the target sum rate.

2021 International Conference on Electrical, Communication, and Computer Engineering (ICECCE), 2021

Due to advancement of wireless communication technology, there is a progressive increase in the n... more Due to advancement of wireless communication technology, there is a progressive increase in the number of devices and connectivity each year and this will inevitably overwhelm the base station with the amount of traffic that it has to handle at a time. Device-to-device communication is one of the most significant aspect technologies in the enhancement of moving towards 5G as it is able to solve this problem. Despite that fact, this solution is entailed with an interference problem whereby the resource blocks need to be allocated efficiently in order to minimize its overall interference effect and maximize its throughput. The D2D communication is then further investigated in a more focused and smaller scale network in which we will create a small system model to study the throughput and interference effect of this type of communication. To ensure minimum interference is caused by the RBs allocation problem, a dynamic spectrum algorithm is preferred than the conventional fixed spectrum allocation. The proposed simulation for this project is done by altering one of the parameters that may or may not influence the overall performance of D2D communication. Based on the simulations performed in this project, it is found that the throughput of the system increased by 40.83% and the interference occurred has also slightly improved by an approximate value of 24.15%. Furthermore, the SINR value of the D2D communication has also improved by a significant value of 66.35%, thus, proving that the scheme proposed in this project succesfully improve the overall interference effect in the D2D communication network system.

2018 5th International Conference on Electrical and Electronic Engineering (ICEEE), 2018

This paper introduces a novel method that allows the presentation of specific, broadband impedanc... more This paper introduces a novel method that allows the presentation of specific, broadband impedances to a DUT by loadpull. To investigate this method, a derivative of class J power amplifier termed BJ is emulated, which effectively lies between class J and class B along the reactive routes on the Smith chart. The mode helps explore baseband linearization approach and its suitability when using continuous mode architectures. Adopting out-of-band impedance optimization technique allows to present impedances and move progressively from a completely real set of loads to completely imaginary set of loads in a deterministic and systematic way. This further extends a view to look at how well the emulated mode linearizes at a set of BJ contour points along the way. The method uses multiple modulated signal sources, phase synchronized at both radio frequency (RF) and intermediate frequency (IF) to provide a complete multi-harmonic broadband loadpull capability controlled by a single local oscillator and allows complete impedance control at the DUT current generator plane.

Applied Sciences, 2022

In this work, we present a resource allocation scheme for managing trade-offs between total throu... more In this work, we present a resource allocation scheme for managing trade-offs between total throughput maximisation and system fairness in a non-orthogonal multiple access (NOMA) system for 5G networks. Our proposed approach is designed to improve throughput and fairness as performance metrics of NOMA in 5G networks. We apply integer linear programming for user pairing and adopt particle swarm optimisation as the power allocation scheme for reducing resource allocation complexity. To formulate the multi-objective problem, we use scalarisation of multi-objective optimisation, which exhibits flexibility in assigning different weights to a single objective—in the case of this study, either sum rate or fairness. Moreover, the problem is formulated with a penalty function to prevent optimisation violating the constraints of the optimisation function. Simulation results show that the proposed model outperformed the conventional approach by at least 17% in terms of throughput maximisation ...

Sensors, 2022

Fifth generation (5G) technology aims to provide high peak data rates, increased bandwidth, and s... more Fifth generation (5G) technology aims to provide high peak data rates, increased bandwidth, and supports a 1 millisecond roundtrip latency at millimeter wave (mmWave). However, higher frequency bands in mmWave comes with challenges including poor propagation characteristics and lossy structure. The beamforming Butler matrix (BM) is an alternative design intended to overcome these limitations by controlling the phase and amplitude of the signal, which reduces the path loss and penetration losses. At the mmWave, the wavelength becomes smaller, and the BM planar structure is intricate and faces issues of insertion losses and size due to the complexity. To address these issues, a dual-layer substrate is connected through the via, and the hybrids are arranged side by side. The dual-layer structure circumvents the crossover elements, while the strip line, hybrids, and via-hole are carefully designed on each BM element. The internal design of BM features a compact size and low-profile stru...

International Journal of Electrical and Computer Engineering (IJECE), 2021

A vital technology in the next-generation cellular network is device-to-device (D2D) communicatio... more A vital technology in the next-generation cellular network is device-to-device (D2D) communication. Cellular user enabled with D2D communication provides high spectral efficiency and further increases the coverage area of the cell, especially for the end-cell users and blind spot areas. However, the implementation of D2D communication increases interference among the cellular and D2D users. In this paper, we proposed a radio resource allocation (RRA) algorithm to manage the interference using fractional frequency reuse (FFR) scheme and Hungarian algorithm. The proposed algorithm is divided into three parts. First, the FFR scheme allocates different frequency bands among the cell (inner and outer region) for both the cellular and the D2D users to reduce the interference. Second, the Hungarian weighted bipartite matching algorithm is used to allocate the resources to D2D users with the minimum total system interference, while maintaining the total system sum rate. The cellular users s...

2021 IEEE 15th Malaysia International Conference on Communication (MICC), 2021

This paper presents a beam forming network using a three-input three-output Butler Matrix which i... more This paper presents a beam forming network using a three-input three-output Butler Matrix which is designed using the slot-coupled transition method. In this method, two sides of the substrate are stacked on top of each other, resulting in a compact size and a non-lossy structure. Unlike the conventional Butler Matrix, this design only requires hybrid couplers and phase shifters while circumvents the crossover structure. In the design of the Butler Matrix, three elliptical slot-coupled hybrids (ESH) with common ground plane are connected to the 0 degree, −90 degree and −180 degree phase shifters which produce the progressive output phase difference of 0 degree, −120 degree, and 120 degree, respectively. When the Butler Matrix with patch antenna array is fed with signals, three beams are created, pointing towards −4 degree, −36 degree, and 29 degree with the gains of 11 dBi, 9.19 dBi, and 11 dBi, respectively. The radiation pattern is generated from the antenna array factor, which derived from the consecutive output phases with λ0/2 antenna spacing at 28 GHz. The system can be a platform for fifth generation (5G) wireless connectivity at millimeter wave.

Journal of Telecommunication, Electronic and Computer Engineering, 2018

In this paper, an investigation of the highpermittivity ceramic-polymer composite antenna is perf... more In this paper, an investigation of the highpermittivity ceramic-polymer composite antenna is performed using Barium Titanate, BaTiO3 nanocomposite ceramic powder mixed with polymer composite of polydimethylsiloxane (PDMS). The ceramic-polymer composite, PDMS-BaTiO3 thin film layer was formed through a spin coating process on the top and the bottom layer of the PDMS substrate for the antenna design in order to achieve an overall antenna size reduction. The proposed patch antennas using the ceramic-polymer composite were analysed at a resonant frequency of 2.45 GHz for WLAN applications regarding antenna performance on return loss, gain, bandwidth, radiation efficiency, and voltage standing wave ratio (VSWR). Two different experimental compositions of 15% and 25% PDMS-BaTiO3 thin film substrate were prepared in the proposed design to create soft, hydrophobic, flexible, resistance against corrosion and lightweight antenna. Significantly, from theoretical analysis and simulation results...