Idnin Pasya

E-shape microstrip patch antenna for wideband applications

This paper presents the design of E-shaped microstrip single patch antenna with wideband operating frequency for wireless application. The antenna design is an improvement from previous research and it is simulated using CST Microwave Studio 2009 software. Parametric study was included to determine affect of design towards the antenna performance. The performance of the designed antenna was analyzed in term of bandwidth, gain, return loss, VSWR, and radiation pattern. The design was optimized to meet the best possible result. Substrate used was C-Foam PF-2 which has a similar dielectric constant of air. The results show the wideband antenna is able to operate from 8.34 GHz to 13.86 GHz frequency band with optimum frequency at 8.73 GHz.

Joint Direction-of-Departure and Direction-of-Arrival Estimation in a UWB MIMO Radar Detecting Targets with Fluctuating Radar Cross Sections

This paper presents a joint direction-of-departure (DOD) and direction-of-arrival (DOA) estimation in a multiple-input multiple-output (MIMO) radar utilizing ultra wideband (UWB) signals in detecting targets with fluctuating radar cross sections (RCS). The UWB MIMO radar utilized a combination of two-way MUSIC and majority decision based on angle histograms of estimated DODs and DOAs at each frequency of the UWB signal. The proposed angle estimation scheme was demonstrated to be effective in detecting targets with fluctuating RCS, compared to conventional spectra averaging method used in subband angle estimations. It was found that a wider bandwidth resulted in improved estimation performance. Numerical simulations along with experimental evaluations in a radio anechoic chamber are presented.

A study on plasma antenna characteristics with different gases

This paper investigates the return loss characteristics of plasma antenna with 3 different gases. For this experiment, 3 plasma antennas were fabricated using glass tubes to contain 3 different gases which are neon, argon and xenon with pressure of 1 Torr. RF heating method was used to ionize the gases into plasma state. The return loss characteristic of each of the fabricated plasma antenna is measured using a vector network analyzer, to demonstrate the capability and potential of the antenna. It was found that the all gas yields return loss below -10 dB in the range of 3.5 GHz to 5.5 GHz. Return loss of the plasma tube with plasma is better than without plasma in all cases. Neon gas yielded a 200 MHz shift in the optimum frequency when measured with plasma.

UWB microstrip antenna based on circular patch topology with stepped blocks (wing)

This paper presents the design of Ultra Wideband (UWB) microstrip antenna consisting of a circular monopole patch antenna with 3 block stepped (wing). The antenna design is an improvement from previous research and it is simulated using CST Microwave Studio software. This antenna was designed on Rogers 5880 printed circuit board (PCB) with overall size of 26 × 40 × 0.787 mm3 and dielectric substrate, εr = 2.2. The performance of the designed antenna was analyzed in term of bandwidth, gain, return loss, radiation pattern, and verified through actual measurement of the fabricated antenna. 10 dB return loss bandwidth from 3.37 GHz to 10.44 GHz based on 50 ohm characteristic impedance for the transmission line model was obtained.

A Frequency Reconfigurable Stacked Patch Microstrip Antenna (FRSPMA) with aperture coupler technique

This paper presents a novel design of a Frequency Reconfigurable Stacked Patch Microstrip Antenna (FRSPMA) by using an aperture coupler as the feeding technique and stacked technology. The proposed antenna was capable to accommodate at S/X band separately by using the same antenna. Two patches at different substrate are activated sequentially by changing the switch mode at the feedline to achieve frequency reconfigurability. Both patches and feedline are electromagnetically coupled through two small electrical apertures in the ground plane. The design was simulated using CST Microwave Studio at operating 2 GHz to 8 GHz. The effect of aperture slots and the switch configuration either at ON or OFF state were studied. The simulation and measured results were analyzed and discussed of return loss, gain, bandwidth and radiation pattern.

Study of monopole plasma antenna using fluorescent tube in wireless transmission experiments

This paper presents a basic study on plasma monopole antenna using a single fluorescent tube and reviews the antenna performance as a transmitter and receiver. In this study, a commercially available fluorescent tube, with 0.31 m length and 0.13 m of diameter is used as the plasma antenna. When the gas inside the tube is sufficiently ionized into plasma state, it becomes conductive and allows radio frequency signals to be transmitted or received. Measurements indicated that the constructed plasma antenna yielded return loss over 10 dB from 805 MHz to 885 MHz frequency band. The antennas capability to operate as either a transmitter or receiver in the particular frequency band was verified through a series of wireless transmission experiments.

Design of a cylindrical parabolic reflector on monopole plasma antenna

A monopole plasma antenna with cylindrical parabolic reflector is proposed. A cylindrical parabolic reflector is placed at the back side of focusing signal to reflect the signal received from transmitter back to the front for increased antenna directivity. The purpose of this design is to enhance the antenna gain and produce strong antenna signal. A monopole plasma antenna positioned at the center of reflector having dimension 310 mm length and 12 mm of diameter is serve as antenna reference. The difference on antenna gain of antenna reference and plasma antenna with reflector was studied throughout the simulations and the performance in terms of return loss and radiation pattern is observed in simulation and measurement results. This antenna is operating at 4.3GHz frequency which is suitable for wireless communication applications.

A monopole fluorescent tube antenna with Wi-Fi Router

A monopole plasma antenna for Wi-Fi application at 2.4 GHz was constructed using a commercially available fluorescent tube. The plasma antenna uses a fluorescent tube with length and diameter of 0.61 m and 0.025 m, respectively. The tube contains a mixture of argon and mercury vapor, which becomes conductive when sufficiently ionized into plasma state, allowing transmissions of radio frequency signal. The constructed plasma antenna was equipped with an access-point WiFi Router which is installed inside the casing of the fluorescent tube. The antennas capability to operate as either a transmitter or receiver in the particular frequency band was verified through a series of wireless transmission experiments. Experimental measurement using a portable spectrum analysis application validated the operability of the constructed antenna.

Investigation of the annual solar eclipse by using Total Electron Content (TEC) measurements

This research investigates the ionosphere response to the annual solar eclipse on 26th January 2009 over Indonesia and Singapore. During solar eclipse, ionosphere will be affect due to the partial or complete obstruction of solar emission. It makes the number of electrons and ions decreases. There are several factors that will contribute to the ionosphere response which are the level of solar and geomagnetic disturbances, geographical latitude and longitude and local time. There are some methods that use to determine the behavior of ionosphere response during solar eclipse. It includes ionosonde measurements, incoherent scatter radar (ISR) and Global Positioning System (GPS) satellite. In this research, GPS satellite is use in order to investigate the ionosphere response. This research focuses on the measurement of Total Electron Content (TEC) obtained from two GPS station which are Bako in Indonesia and Ntus in Singapore. The location of these three GPS stations from the path of solar eclipse occur is different. The data is obtained a day before and during solar eclipse. From the findings it shows that TEC level will reduce during solar eclipse due to the reduction of ionizing radiation.

Tuning circuit using varactor diode for tunable bandstop resonator

A tuning circuit based on the use of varactor is presented to tune the electrical length of an open-circuited stub. The complete circuit with the choice of components is given in the paper, along with its simulation results. The proposed circuit is realized using microstrip technology on FR4 substrate. The experimental results are found to be of good agreement with the ones obtained from simulation. The proposed circuit is expected to be advantageous for future tuning applications of bandpass filter. The experimental result shows the center frequency of tunable filter can be tuned up to 84%.