M. A. Mutalib

Dual-band monopole antenna for energy harvesting system

A planar dual-band monopole antenna is presented for Global System for Mobile Communications (GSM) band applications, which also have the potential to be used for energy harvesting system. The proposed antenna comprises of a ground plane at the back of the FR4 substrate and three microstrip lines which are physically connected with each other at the top surface of the substrate. The monopole antenna achieves good return loss at resonance frequencies of 915 MHz and 1800 MHz with a bandwidth value of 124.2 MHz and 196.9 MHz respectively. The antenna gains of 1.97 dB and 3.05 dB are achieved at resonance frequencies of 900 MHz and 1800 MHz. Experimental results show good agreement with simulated performance. The output from the receiving antenna is also observed in order to analyze the relationship of the power level and the distance between transmitting and receiving antenna. This study is an early investigation in designing the RF energy harvesting system to support green technology and sustainable development particularly for Wireless Sensor Network (WSN) applications.

Transformation of generalized chebyshev lowpass filter prototype to Suspended Stripline Structure highpass filter for wideband communication systems

This paper presents the transformation of generalized Chebyshev lowpass filter prototype to highpass filter using Suspended Stripline Structure (SSS) technology. The study involves circuit analysis to determine generalized Chebyshev responses with a transmission zero at finite frequency. The transformation of the highpass filter from the lowpass filter prototype provides a cutoff frequency of 3.1 GHz with a return loss better than -20 dB. The design is simulated on a Roger Duroid RO4350 with a dielectric constant, εr of 3.48 and a thickness of 0.168 mm. The simulation performance results show promising results that could be further examined during the experimental works. This class of generalized Chebyshev highpass filter with finite transmission zero would be useful in any RF/ microwave communication systems particularly in wideband applications where the reduction of overall physical volume and weight as well as cost very important, while maintaining its excellent performance.

A compact DMS triple-band bandstop filter with U-slots for communication systems

This paper presents compact structure of bandstop filter with Defected Microstrip Structure (DMS) to produce a triple - band reject response. To prove the concept of the narrow notched DMS, the operating on centre frequency of 4.0 GHz is demonstrated and validated through simulation. The DMS structure is embedded in the middle of transmission lines in order to reject any undesired signals which may interfere with any communication systems. The design was simulated based on Roger Duroid RO4350B with a thickness of 0.508 mm and dielectric constant of 3.48. This type of filter is useful in any RF/ microwave communication systems, particularly to eliminate any undesired signals in wideband spectrum. While maintaining its excellent performance, the overall physical and cost reduction can also be achieved using this technique.

Design of generalized Chebyshev lowpass filter with Defected Stripline Structure (DSS)

This paper presents the design of generalized Chebyshev lowpass filter (LPF) and integrated with Defected Stripline Structure (DSS) using Suspended Stripline Structure (SSS). The study involves circuit analysis to determine generalized Chebyshev responses with a transmission zero at finite frequency in order to produce a reduced number of elements values of prototype circuit. The LPF provides a cut-off frequency at 6 GHz with a return loss better than -19 dB, while the DSS exhibits a notch at frequency of 3.2 GHz with a stopband response better than -40 dB. Thus, the integrated LPF and DSS will produce lowpass and band reject response simultaneously. The design is implemented on a Roger Duroid RO4350 with a thickness of 0.168 mm and dielectric constant, εr of 3.48. The simulation performance results show promising results that could be proved in the experiment works. This new class of integrated LPF and DSS would be useful in any RF/ microwave communication systems particularly in wideband applications where the reduction of overall physical volume, weight and cost is critical to maintaining its good performance.

Design of microstrip bandpass filter with electronically tunable notch response

An integrated high selectivity microstrip wideband bandpass filter with tunable notch response is presented in this paper. The bandpass filter is designed using 7th order short circuited stub filter. Then, the first short circuited stub is replaced with two sections of open circuited stub to exhibit the transmission zeros at lower/higher stopband. The integration with notch filter is realized using U-shape Defected Microstrip Structure (DMS) with varactor diode. By properly varying the DC bias voltages, the notch response can be tuned over a constant bandwidth of around 17%. The experimental result shows that the bandwidth of the wideband bandpass filter is between 2.9 GHz - 5.8 GHz. The notchs tuning range from 4 GHz to 5 GHz is achieved using varactor diode respectively. This type of filter is suitable for applications such as the multi-service and multiband communication system in order to discriminate the undesired signals.

The investigation of reconfigurable SIW filter using varactor diodes

This paper introduces a novel reconfigurable SIW filter for 4G applications by using varactor diodes. This SIW filter consists of two floating islands with two via holes that connected with two varactor diodes. This method allows designing SIW filter with the tunable centre frequency with a constant absolute bandwidth. The filter is designed through the simulation on a standard printed circuit board technology. The SIW filter at 2.097 GHz shows an insertion loss of 1.87 dB and 3 dB bandwidth of 163.39 MHz. SIW filter is used to obtain a good performance that suitable for integration with any reconfigurable planar structure. This investigation provides an alternative solution for reconfigurable SIW filter, particularly in 4G communication systems.

Tunable notch response for ultra wide-band bandpass filter

A design of ultra wide-band microstrip bandpass filter with tunable notch response of wireless communication system is presented in this paper. The five order bandpass filter is designed using optimum distributed highpass integrated with Defected Microstrip Structure (DMS). The bandpass filter was designed at wideband frequency from 3.1GHz to 10.6GHz. The insertion loss and return loss of this project is set to better than 0.5dB and 20dB respectively. The DMS is implemented in this design in order to remove undesired frequency in wireless communication system. The pin diode is added to act as a switch to tuning the notch response. When the pin diode off, the notch response produce a sharp response at 5.906GHz (WLAN). When the pin diode on, the notch response is removed from the passband and provide full UWB passband. This design is simulated by ADS software and using Roger Duroid 4350B with a dielectric constant of 3.48, substrate thickness 0.508mm and loss tangent 0.0019.

Investigation of Compact Tree-Shaped Coplanar Waveguide (CPW) Antenna for RF Energy Harvesting

This paper studies a compact wideband tree-shaped coplanar antenna which has the potential to be used for RF energy harvesting. The antenna is fabricated on a double-sided FR-4 printed circuit board using an etching technique. The effect of semi-circle patch embedded to a triangular patch has been studied. The comparison between simulation and measurement results for the return loss and radiation patterns are observed and are in good agreement. The measured return loss is in line with the simulation response where both manage to achieve lower than-10dB. A bandwidth of 3.64 GHz and 3.94 GHz were obtained in simulation and measurement process respectively. This study is an early investigation in designing the antenna for RF energy harvesting system to support green technology and sustainable development particularly for Wireless Sensor Network (WSN).

Investigation of meander slots to microstrip patch patch antenna

Microstrip slotted meander line antenna with a diverse number of meander slots is presented for 2.4 GHz of Wireless Local Area Network (WLAN) application. The proposed antenna comprises a rectangular microstrip patch element embedded with several numbers of meander slots in many positions. The parametric study is performed to investigate the characteristic of these microstrip patch antennas with different numbers of meandered slots. Many designs of slotted meander line antenna are produced and they are analyzed based on the number of slotted meander line used. Antenna with 7 slotted meander lines has the most size reduction of approximately 23% of the original size. This study is an early investigation in designing the RF energy harvesting to support green technology and sustainable development particularly for Wireless Sensor Network (WSN) as well as Radio Frequency Identification (RFID) applications.