yusnita rahayu - Academia.edu (original) (raw)

Papers by yusnita rahayu

... 2. Fourth Generation, 4G 4G, the successor of 3G and is a wireless access technology. It desc... more ... 2. Fourth Generation, 4G 4G, the successor of 3G and is a wireless access technology. It describes two different but overlapping ideas. The IEEE official name for 4G is "3G and beyond". ... The CP is obtained by copying the last v samples of each block to the beginning ofthe block. ...

The restricted spectrum frequency and the narrow handwidth allocated by regulatory organizations ... more The restricted spectrum frequency and the narrow handwidth allocated by regulatory organizations to wireless users impacts the design of the RF front end. Narrowband amplification and filtering to avoid leakage to adjacent hands is required for transmitter design. Power spectrum of transmitter must not exceed the limits of spectral power density 111. This paper presents a 23GHz transmitter system for point-to-point microwave link. Linearity requirements for the transmitter need to he considered in order to have high power transmit. The system is designed with Advanced Design Software (ADS). A 23 GHz transmitter comprises a double conversion up-converter. The simulation result of power transmit is 21.516 dBm. This is obtained over the 22.999 -23.549 GHz frequency range. The design of transmitter is the proper choosing and arrangement of microwave components to meet the European Telecommunications Standirds Institute (ETSI) recommendations for point-to-point equipment in fued radio systems operating at 23 GHz 111. Keywords-transminer design, point-to-point microwave link, 23 CHz, linear@, system level.

Due to rapid advancement in microwave communication technologies in telecommunication and broadca... more Due to rapid advancement in microwave communication technologies in telecommunication and broadcasting has resulted in congestion for frequencies below 10 GHz. This fact has forced to the utilization of higher frequencies extending the radio frequency spectrum into the millimeter wavelength region. This paper presents the system design of a 23 GHz transceiver for point-to-point microwave link. The designed system is simulated using Advanced Design System (ADS) for component specifications determination and performance measurement. The effect of rain attenuation to the system is analysed, as to determine the effectiveness of the system. The design of transceiver involves the proper selection and arrangement of microwave components to meet the European Telecommunications Standards Institute (ETSI) recommendations for point-to-point equipment in fixed radio systems operating at 23 GHz.

The radio spectrum is finite, but bandwidth utilization for wireless communication is increasing ... more The radio spectrum is finite, but bandwidth utilization for wireless communication is increasing exponentially due to the emergence of new standards driven by the rapid growth in information services provided by the Internet. Therefore, there is a need for new technology that can open a new door to wireless communication. Ultra wideband (UWB) technology based on the use of very

This paper presents an active photonic antenna concept whereby an interface circuit is introduced... more This paper presents an active photonic antenna concept whereby an interface circuit is introduced in order to integrate the antenna with the photodiode. The operating frequencies ranges are 1.8 to 3.5 GHz which support the GSM 1800, WLAN and WiMAX applications. The simulated and measured results of interface circuit and antenna are presented. Thus, the photonic antenna is developed by integrating photodiode, interface circuit, RF amplifier and printed antenna and fabricated on FR4 board. The experiment was setup and spectrums at desired frequencies were measured. Measurement results show that an active downlink photonic antenna (ADPha) is successfully developed.

This paper presents various slotted antenna. The proposed antenna is designed in order to meet Ul... more This paper presents various slotted antenna. The proposed antenna is designed in order to meet Ultra Wideband (UWB) requirements and applications. This antenna has small in size enabling it to be fixed into Wireless Personal Area Network (WPAN) devices. There are three types of proposed slotted antennas; T slotted for patch and feeding strip, couple a ring and L slots, and dual asymmetry L slots. From the simulation results, matching bandwidth is due to the shape of the antenna close to the feeding point, where currents are the strongest. It is shown that to better control an antenna behavior, it is necessary to observe the current distributions which give most contribution on matching performance. The T slot on the feeding strip produces more vertical current thus improve the matching impedance performance at higher frequencies, the ring slot with the open angle of 90° and radius (r1) of 3 mm has shown an improvement to the return loss at the lower resonance of 5 GHz and the upper resonance of 10 GHz, the dual asymmetry L slot on rectangular patch has shown multiple resonances. Their simulated return loss and radiation pattern meet the UWB requirements. The slot types are as novelty for this work.

In choosing an antenna topology for ultra wideband (UWB) design, several factors must be taken in... more In choosing an antenna topology for ultra wideband (UWB) design, several factors must be taken into account including physical profile, compatibility, impedance bandwidth, radiation efficiency, and radiation pattern. In this paper, a small compact T slots UWB antenna is presented. It originates from conventional rectangular monopole and is realized by adding T slots for both patch and feeding strip. The wideband behaviour is due to the fact that the currents along the edges of the slots introduce an additional resonance, which, in conjunction with the resonance of the main patch, produce an overall broadband frequency response characteristic. The slots also appear to introduce a capacitive reactance which counteracts the inductive reactance of the feed. Thus, the bandwidth broadening comes from the patch and T-slots, coupled together to form two resonances. The effect of current distributions of the T slots was simulated by using Zeland FDTD. The measured return loss of this proposed antenna is also presented as well.

This paper presents a small printed ultra wideband (UWB) antenna with a coupled slot. This propos... more This paper presents a small printed ultra wideband (UWB) antenna with a coupled slot. This proposed antenna uses coupled L and U slots to broaden the bandwidth. A truncated ground plane is designed to control the antenna's impedance matching. Both slots were designed by investigating the behaviour of the current distribution of the patch antenna. It is shown that by proper design of the slot width and length of those coupled slots, without degrading their performance, a broad bandwidth can be obtained. The antenna's dimension is 30 mm × 30 mm and fed by microstrip line. Both simulated and measured results have shown a good return loss with respect to -10 dB and nearly omni-directional pattern over 2.5 GHz to 10.1 GHz. Thus, this proposed antenna is as potential candidate in UWB application.

This paper presents a wideband photonic antenna consisting the laser diode, matching circuit, RF ... more This paper presents a wideband photonic antenna consisting the laser diode, matching circuit, RF amplifier and microstrip patch antenna are fabricated and connected together to perform in uplink system. Laser driver is used to supply the dc biasing for the laser. Lastly, the LD-matching circuit, RF amplifier and antenna were arrange together and connected to perform the wireless uplink system. The simulated and measured results are presented and discussed. These results show useful photonic antenna design that achieves relatively wide bandwidth and has potential to be applied in RoF technology.

... Tharek A. Rahman2, Razali Ngah2 Wireless Communication Centre (WCC) Faculty of Electrical Eng... more ... Tharek A. Rahman2, Razali Ngah2 Wireless Communication Centre (WCC) Faculty of Electrical Engineering Universiti Teknologi Malaysia (UTM) Johor Bahru, 81310, Malaysia tharek@fke.utm.my, razalin@fke.utm.my ... [4] Yusnita Rahayu, Tharek A. Rahman, Razali Ngah, ...

This paper reports on the characterization of non-scalable square spiral inductors based on 0.15 ... more This paper reports on the characterization of non-scalable square spiral inductors based on 0.15 μm GaAs pHEMT technology. The effect of number of turns on the electrical characteristics of the spiral inductors were characterized up to 40 GHz with inductances values obtained from 0.241 to 2.436 nH. The inductance and self resonant frequency (SRF) of the square spiral inductors were determined by S-parameter simulations from the Smith chart. Results show that the spiral inductors have resonance frequencies ranging from 13.52 GHz to more than 30 GHz for spiral inductors values from 2.436 nH to 0.241 nH. Using tune-tank circuit topology, the Q factor obtained for the spiral inductors have values ranging from 11 to 16. The spiral inductors behavior was finally represented by a π-network equivalent circuit based from on-wafer S-parameter measurement.

... 2. Fourth Generation, 4G 4G, the successor of 3G and is a wireless access technology. It desc... more ... 2. Fourth Generation, 4G 4G, the successor of 3G and is a wireless access technology. It describes two different but overlapping ideas. The IEEE official name for 4G is "3G and beyond". ... The CP is obtained by copying the last v samples of each block to the beginning ofthe block. ...

The restricted spectrum frequency and the narrow handwidth allocated by regulatory organizations ... more The restricted spectrum frequency and the narrow handwidth allocated by regulatory organizations to wireless users impacts the design of the RF front end. Narrowband amplification and filtering to avoid leakage to adjacent hands is required for transmitter design. Power spectrum of transmitter must not exceed the limits of spectral power density 111. This paper presents a 23GHz transmitter system for point-to-point microwave link. Linearity requirements for the transmitter need to he considered in order to have high power transmit. The system is designed with Advanced Design Software (ADS). A 23 GHz transmitter comprises a double conversion up-converter. The simulation result of power transmit is 21.516 dBm. This is obtained over the 22.999 -23.549 GHz frequency range. The design of transmitter is the proper choosing and arrangement of microwave components to meet the European Telecommunications Standirds Institute (ETSI) recommendations for point-to-point equipment in fued radio systems operating at 23 GHz 111. Keywords-transminer design, point-to-point microwave link, 23 CHz, linear@, system level.

Due to rapid advancement in microwave communication technologies in telecommunication and broadca... more Due to rapid advancement in microwave communication technologies in telecommunication and broadcasting has resulted in congestion for frequencies below 10 GHz. This fact has forced to the utilization of higher frequencies extending the radio frequency spectrum into the millimeter wavelength region. This paper presents the system design of a 23 GHz transceiver for point-to-point microwave link. The designed system is simulated using Advanced Design System (ADS) for component specifications determination and performance measurement. The effect of rain attenuation to the system is analysed, as to determine the effectiveness of the system. The design of transceiver involves the proper selection and arrangement of microwave components to meet the European Telecommunications Standards Institute (ETSI) recommendations for point-to-point equipment in fixed radio systems operating at 23 GHz.

The radio spectrum is finite, but bandwidth utilization for wireless communication is increasing ... more The radio spectrum is finite, but bandwidth utilization for wireless communication is increasing exponentially due to the emergence of new standards driven by the rapid growth in information services provided by the Internet. Therefore, there is a need for new technology that can open a new door to wireless communication. Ultra wideband (UWB) technology based on the use of very

This paper presents an active photonic antenna concept whereby an interface circuit is introduced... more This paper presents an active photonic antenna concept whereby an interface circuit is introduced in order to integrate the antenna with the photodiode. The operating frequencies ranges are 1.8 to 3.5 GHz which support the GSM 1800, WLAN and WiMAX applications. The simulated and measured results of interface circuit and antenna are presented. Thus, the photonic antenna is developed by integrating photodiode, interface circuit, RF amplifier and printed antenna and fabricated on FR4 board. The experiment was setup and spectrums at desired frequencies were measured. Measurement results show that an active downlink photonic antenna (ADPha) is successfully developed.

This paper presents various slotted antenna. The proposed antenna is designed in order to meet Ul... more This paper presents various slotted antenna. The proposed antenna is designed in order to meet Ultra Wideband (UWB) requirements and applications. This antenna has small in size enabling it to be fixed into Wireless Personal Area Network (WPAN) devices. There are three types of proposed slotted antennas; T slotted for patch and feeding strip, couple a ring and L slots, and dual asymmetry L slots. From the simulation results, matching bandwidth is due to the shape of the antenna close to the feeding point, where currents are the strongest. It is shown that to better control an antenna behavior, it is necessary to observe the current distributions which give most contribution on matching performance. The T slot on the feeding strip produces more vertical current thus improve the matching impedance performance at higher frequencies, the ring slot with the open angle of 90° and radius (r1) of 3 mm has shown an improvement to the return loss at the lower resonance of 5 GHz and the upper resonance of 10 GHz, the dual asymmetry L slot on rectangular patch has shown multiple resonances. Their simulated return loss and radiation pattern meet the UWB requirements. The slot types are as novelty for this work.

In choosing an antenna topology for ultra wideband (UWB) design, several factors must be taken in... more In choosing an antenna topology for ultra wideband (UWB) design, several factors must be taken into account including physical profile, compatibility, impedance bandwidth, radiation efficiency, and radiation pattern. In this paper, a small compact T slots UWB antenna is presented. It originates from conventional rectangular monopole and is realized by adding T slots for both patch and feeding strip. The wideband behaviour is due to the fact that the currents along the edges of the slots introduce an additional resonance, which, in conjunction with the resonance of the main patch, produce an overall broadband frequency response characteristic. The slots also appear to introduce a capacitive reactance which counteracts the inductive reactance of the feed. Thus, the bandwidth broadening comes from the patch and T-slots, coupled together to form two resonances. The effect of current distributions of the T slots was simulated by using Zeland FDTD. The measured return loss of this proposed antenna is also presented as well.

This paper presents a small printed ultra wideband (UWB) antenna with a coupled slot. This propos... more This paper presents a small printed ultra wideband (UWB) antenna with a coupled slot. This proposed antenna uses coupled L and U slots to broaden the bandwidth. A truncated ground plane is designed to control the antenna's impedance matching. Both slots were designed by investigating the behaviour of the current distribution of the patch antenna. It is shown that by proper design of the slot width and length of those coupled slots, without degrading their performance, a broad bandwidth can be obtained. The antenna's dimension is 30 mm × 30 mm and fed by microstrip line. Both simulated and measured results have shown a good return loss with respect to -10 dB and nearly omni-directional pattern over 2.5 GHz to 10.1 GHz. Thus, this proposed antenna is as potential candidate in UWB application.

This paper presents a wideband photonic antenna consisting the laser diode, matching circuit, RF ... more This paper presents a wideband photonic antenna consisting the laser diode, matching circuit, RF amplifier and microstrip patch antenna are fabricated and connected together to perform in uplink system. Laser driver is used to supply the dc biasing for the laser. Lastly, the LD-matching circuit, RF amplifier and antenna were arrange together and connected to perform the wireless uplink system. The simulated and measured results are presented and discussed. These results show useful photonic antenna design that achieves relatively wide bandwidth and has potential to be applied in RoF technology.

... Tharek A. Rahman2, Razali Ngah2 Wireless Communication Centre (WCC) Faculty of Electrical Eng... more ... Tharek A. Rahman2, Razali Ngah2 Wireless Communication Centre (WCC) Faculty of Electrical Engineering Universiti Teknologi Malaysia (UTM) Johor Bahru, 81310, Malaysia tharek@fke.utm.my, razalin@fke.utm.my ... [4] Yusnita Rahayu, Tharek A. Rahman, Razali Ngah, ...

This paper reports on the characterization of non-scalable square spiral inductors based on 0.15 ... more This paper reports on the characterization of non-scalable square spiral inductors based on 0.15 μm GaAs pHEMT technology. The effect of number of turns on the electrical characteristics of the spiral inductors were characterized up to 40 GHz with inductances values obtained from 0.241 to 2.436 nH. The inductance and self resonant frequency (SRF) of the square spiral inductors were determined by S-parameter simulations from the Smith chart. Results show that the spiral inductors have resonance frequencies ranging from 13.52 GHz to more than 30 GHz for spiral inductors values from 2.436 nH to 0.241 nH. Using tune-tank circuit topology, the Q factor obtained for the spiral inductors have values ranging from 11 to 16. The spiral inductors behavior was finally represented by a π-network equivalent circuit based from on-wafer S-parameter measurement.