Syarfa Zahirah Sapuan

Analytical Solution for Maximum Differential-Mode Radiated Emissions of Microstrip Trace

In this paper, a novel analytical solution was presented for estimating the maximum differential-mode (DM) radiated emission from electrically long PCB traces using transmission-line theory, travelling wave antenna, and far-field magnetic vector potential. The analytical solution was simplified for matched load in which only forward travelling wave was considered. Additionally, a simple expression for predicting maximum DM-RE from electrically short traces was obtained using proper simplifications. The results from the proposed analytical model were then compared to the results obtained from 3-D HFSS full-wave simulation and the measurement performed in a semianechoic chamber. Good agreements within ±3 dB were obtained over a wide range of frequency.

Calculable antenna factor of a biconical reference antenna

Calculable antenna is used as a reference antenna for antenna calibration to obtain accurate antenna factor. This paper focuses on calculable biconical antenna with low uncertainty. The proposed biconical antenna factor can be derived either by simulation or by analytical method. The antenna factor is directly derived from antenna gain. Therefore, the uncertainty could be improved due to no measurements involved. The antenna factor versus frequency is presented for frequency range 200 MHz up to 2GHz.

Direct feed biconical antenna as a reference antenna

Antenna factor is the main parameter in EMC measurement. Therefore, accurate and low uncertainty antenna is important in order to gain a reliable antenna factor. Direct feed biconical antenna has low uncertainty because balun can be eliminated in the design. Furthermore, the biconical antenna has fix phase center. This paper focuses on type of connectors and antenna sizes that are suitable to be used as a calibration antenna. The return loss for frequency range between 200Mz to 2GHz was measured using network analyzer and found to vary between 10dB to 20dB.

Issue on Calibration of Direct Feed Biconical Antenna in a Semi-Anechoic Chamber Using Standard Antenna Method

Antenna calibration is crucial to ensure the accuracy of Electromagnetic Compatibility (EMC) measurement results. Standard Antenna Method (SAM) is one of the methods widely used in antenna calibration which requires reference antenna with known Antenna Factor (AF) in a free space environment. The work presented in this paper is on the calibration of the AF of a direct-feed biconical antenna in a semi-anechoic chamber (SAC) with considerations given to the effects of ground plane, antenna height, reference antenna type and effects of phase center. The frequency range for the analysis is from 200 MHz to 2 GHz. It is found that antenna located 1.5 m from ground provides the best result compared to modeling. In addition, the phase centers of the reference and test antenna must be at the same positions during the measurements.

Shielding Effectiveness of a Rectangular Enclosure with Aperture and Wire Penetration

An enclosure without aperture and wire penetration are impracticable due to the requirement for ventilation and cables. This paper is written to present the measurement of shielding effectiveness (SE) and S21 for such enclosure at frequencies below 1 GHz. The measurement results indicate that a wire or cable penetrating into an enclosure has impact to the shielding effectiveness. The coupling between a wire penetration and a detector inside the enclosure show good agreement between experiment and simulation. All results indicate the same resonant frequency approximately 707.1 MHz for a 300 times 120 times 300 mm enclosure.

Shielding effectiveness and S 21 of a rectangular enclosure with aperture and wire penetration

Shielding effectiveness is a major problem to prevent electronic products from emission and radiation. This paper is written to present the measurement of shielding effectiveness (SE) and S21 for such enclosure at frequencies below 1GHz. The measurement results indicate that a wire or cable penetrating into an enclosure has impact to the shielding effectiveness. The coupling between a wire penetration and a detector inside the enclosure show good agreement between experiment and simulation. The different length and direction of a wire penetration were used to interpret the theory. All results indicate the same resonant frequency approximately 707.1MHz for a 300 x 120 x 300 mm enclosure.

Neural network based model for radiated emissions prediction from high speed PCB traces

Printed Circuit Board (PCB) traces are one of most important PCB Radiated Emissions (RE) sources. These traces is becoming electrically long as the trace length is comparable with the wavelength resulting in higher RE. Therefore, it is essential to predict the RE to avoid out of compliance test issues. In this paper, a neural network Multi-Layer Percetron (MLP) model is developed to predict the radiated emissions of PCB traces. The MLP model is then trained and tested using data set generated based recently developed closed-form equations. Results had shown that a good estimate of the radiated emissions can be obtained using this developed model avoiding both the time-consuming simulations and expensive prototype testing in the compliance chambers. Double-layer PCB is fabricated to validate the proposed neural network model by measurement in a Semi Anechoic Chamber (SAC). Moreover, reasonable agreements are obtained between the measurement and proposed model results.

EMC management and control plan for mass rapid transit railway project in Malaysia

Today, railways have numerous communication, navigation, propulsion, power and control systems. These systems are operating in a very limited space resulting in significant interference issues. Therefore, it is crucial to take into the account the Electromagnetic Compatibility (EMC) through the project life time starting in the design stage. This paper presents briefly the EMC management and control plan of Mass Rapid Transit (MRT) to ensure that the various railway subsystems can function satisfactorily in their intended electromagnetic environment. The EMC approach taken in the MRT Railway project in Malaysia is outlined in this paper. All the MRT railway communications systems should not disturb the operation of each other or the other nearby systems. These communications systems should not be also susceptible to any intentional/unintentional EMI sources in the MRT railway environment. The EMC management and control plan is helpful to avoid EMC/EMI issues of MRT such as EMI sources/ victims identification and risk assessment starting from the design to commissioning. Commonly, all the equipment on the railway must comply to the relevant EMC railway standards such as EN50121. Furthermore, cable management is significantly considered especially for very limited spaces such as tunnels. Finally, the necessary mitigation techniques are recommended to overcome the unexpected EMC challenges which may occur after commissioning.

Harmonic suppression using rectangular defected ground structure

This paper is on the design and performance of a wide rectanglular microstrip antennas with slots that cover frequency of 900 MHz, 1800 MHz, 2100 MHz also 2600 MHz using defected ground structure (DGS) with minimum complexity of antenna design to achieve wideband harmonic suppression. Nowadays, there are numerous aspects need to be considered in designing an antenna. Harmonic suppression antenna (HSA) is able to suppress the harmonic frequencies to get a better singleband antenna performance since the antenna only operate and radiate at single frequency. To achieve this, two rectangular DGS (RDGS) with different positions and dimensions are etched on the ground plane. Simulated and measured return losses results indicate that proposed structure effectively suppress the harmonics up to 35 dB between 3 GHz and 11 GHz with a maximum ripple of 2 dB.

Time domain analysis of direct-feed biconical antenna for Antenna calibration and EMC measurement

The direct-feed biconical antenna where no balanced to unbalanced network (BALUN) is needed has been used in Antenna calibration and Electromagnetic Compatibility (EMC). It has optimized dimensions using mathematical method to match 50 Ω systems between 200 MHz and 2 GHz. Antenna Factor has been determined for proposed direct feed biconical antenna. However, the analytical results have deviation up to 5dB at 300 MHz compared with simulation and measurement results. This is predicted due to the gap between two cones in simulation and measurement. In analytical, assumption has been made that the gap between two cones is ignored. Therefore, time domain analysis using a time gating method has been used to analyse the effect between two cones. The results shows that the gap between two cones and the connector that been used in both simulation and measurement that was not taken into consideration in the AF evaluation in the analytical method could affect the input impedance and eventually give high uncertainty to the AF especially at low frequency.