Rashidah Che Yob
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Rashidah Che Yob
Official Name
Rashidah, Che Yob
Alternative Name
Yob, Rashidah Che
Che Yob, Rashidah
Yob, R. C.
Main Affiliation
Scopus Author ID
57215009095

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Artificial Magnetic Conductor to Enhance Microstrip Patch Textile Antenna Performance for WiMAX Application

2020-12-18 , Zahid L. , Abu Bakar H. , Abdul Rani K.N. , Thennarasan Sabapathy , Mohd Aminudin Jamlos , Mohamad Rizal Abdul Rejab , Musa K.S. , Hamzah D. , Norfatihah Bahari , Rashidah Che Yob

A rectangular microstrip patch textile antenna with Artificial Magnetic Conductor (AMC) operated at the center frequency of 5.80 gigahertz (GHz) for Worldwide Interoperability for Microwave Access (WiMAX) application was designed and simulated using the CST Microwave Studio 2016 and fabricated in this study. The use of AMC could solve the inflexibility of FR4 substrate that limits human body movement and reduce the radiation scattered on the human body whilst increasing the antenna gain and directivity. The antenna consists of 5 5 square shape gap of AMC unit cells ground layer using ShieldIt Super, five substrate layers using cotton (viscose) fabric as well as patch layer and another ground layer using the same ShieldIt Super. AMC is a metamaterial that imitates the conduct of zero reflection phase of Perfect Magnetic Conductor (PMC) on the resonant frequency not evidently existed in nature. Overall, the antenna with AMC has the significant return loss, S11 below than -30 decibel (dB), gain improved to more than 8 dB, and directivity elevated to more than 9 dBi at resonant frequency near to 5.80 GHz, respectively.

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Left-Handed Metamaterial Wearable Antenna at 5G Frequency Range for Wireless Body Area Network

2023-01-01 , Ramli N.H. , Lokman M.A.F. , Norfatihah Bahari , Liyana Zahid , Rashidah Che Yob , Mohd Hafizuddin Mat , Mohd Aminudin Jamlos , Alzubaidi L.H. , Hussein A.H.A.

Wearable antennas are typically required to be small in weight, provide high bandwidth, high gain and efficiency, low price, and be installation-free for many modern applications. Due to the non-static human movement, an antenna with wide-angle scanning is necessary. This project is carried out by designing a small metamaterials wearable antenna at a 5G frequency range. The combination of left-handed metamaterial (LHM) and the wearable antenna is designed to operate for such a system. Results prove that the small wearable metamaterial antenna offers good performances where the gain is 5.8 dBi with an efficiency of 91.86% and provides an omnidirectional radiation pattern compared to the wearable antenna without LHM structure. The communication links of the antenna between the base station and the human body are investigated. The antenna can receive the signals for long distances may be up to 2 meters with wide angles. All the results will be a guideline while designing the systems in the future.

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Cylindrical Dielectric Resonator as Dielectric Matching on Microwave Amplifier for the Unconditionally Stable and Conditionally Stable Transistor at 5 GHz Frequency

2022-12-01 , Rashidah Che Yob , Mahyuddin N.M. , Ain M.F. , Mohd Aminudin Jamlos , Nur Hidayah Ramli , Norfatihah Bahari , Mohd Wafi Nasrudin , Liyana Zahid

Stability and matching techniques on microwave amplifier have been an important consideration to maintain their required performances, but typically its frequency dependent. Thus, a frequency variable mechanism is required. The dielectric matching employing the stability and matching techniques on microwave amplifier with cylindrical dielectric resonator has been investigated and realized. The cylindrical dielectric resonator (CDR) with parallel microstrip lines is proposed at 5 GHz frequency for unconditionally stable and conditionally stable transistor as dielectric matching. Hence, the proposed dielectric resonator with +2 mm spacing and 155Ëš of curved configuration indicated the best performances for preliminary study. The result improves the performance of the parallel inhomogeneous CDR by 9.77%. Subsequently, the homogeneous CDR is also successfully working as the variable frequency mechanism for unconditionally stable and conditionally stable transistor at 5 GHz frequency in maintaining their stability performances.

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Smart Management Waiting System for Outpatient Clinic

2023-02-01 , Mohd Wafi Nasrudin , Zainuddin N.S.A. , Raja Abdullah Raja Ahmad , Rashidah Che Yob , Mohd Zamri Zahir Ahmad , Wan Azani Wan Mustafa , Vijayasarveswari Veeraperumal , Zulkifli N.D.M.

Queuing has become a common occurrence in malls, train stations, and others. Queuing especially in healthcare intuitions has become a center of attraction because of the long waiting time either at the registration or in receiving treatments. Therefore, in solving this problem, a smart management waiting system for outpatient clinics is developed by using AppGyver and Backendless as the data storage. This system will be operating by QR code scanning for administrators to obtain patients’ personal information before patients obtain the queue number via MyQUEUE mobile application (patients’ interface). By providing queue numbers through the mobile application, patients don’t have to wait in a small uncomfortable waiting lounge instead patients can wait at their desired places such as cafeteria, in their car, and others. Patients also don’t have to worry about missing their turns because there will be a 10 minutes reminder before their turn. Other than that, there is a feature that digitalized the appointment details which means patients don’t have to worry about missing their appointment book or card. The performance of both systems which are the patients’ interface and administrators’ interface is successfully designed and the output obtained. The administrator is able to assign queue numbers, notify patients 10 minutes before consultation time, and assign follow-up appointments to patients.

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Antenna Performance Enhancement using AMC Structure for 5G Frequency Range

2023-02-01 , Norfatihah Bahari , Rokhizan M.Z.N. , Rashidah Che Yob , Mohd Wafi Nasrudin , Nur Hidayah Ramli , Mohd Aminudin Jamlos , Lago H.

This paper presents a microstrip patch antenna operated at the fifth generation (5G) frequency range, which is at 3.5 GHz. To enhance the performance of the proposed antenna, an Artificial Magnetic Conductor (AMC) structure is implemented into the design. The 1x3 AMC is sandwiched between two FR-4 substrates and the performance of the proposed antenna is compared with the antenna without AMC structure. The simulated results prove that the proposed antenna offers better reflection coefficient with-50.45 dB compared to only-15.55 dB for the conventional antenna. Wider bandwidth is also achieved with 427 MHz of frequency bandwidth as opposed to only 135 MHz for the antenna without AMC. Besides that, the integration of AMC enhances the gain of the antenna when 3.7 dBi is achieved in contrast to only 3.21 dBi for the conventional antenna. Moreover, the efficiency of the antenna with AMC is also improved up to 68.54%. Furthermore, the ability to shrink 52.23% of the size of the antenna without AMC making it very favorable to be applied in 5G bands.

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