Micro-flexographic is a new printing technique that has been implemented by combining flexographic printing and micro-contact printing technique. Flexographic printing is generally a high-speed production in roll to roll printing technique widely used in the graphic printing industry. Micro-contact printing technique is usually employed to produce fine solid line structures in micro to nano scale. Mould preparation for printing plate is also one of the vital parameters in micro to nano scale image printing. A precise mould could be used to produce the most accurate printing plate for micro-flexographic printing. The three dimension (3D) printer has the capability of producing fine solid lines below 100 μm in width and gap on master mould for the printing industry. This research elaborated the use of various 3D printers to produce a master mould for micro-flexographic printing. This paper investigated the capability of multiple 3D printers in creating micro to nano fine solid lines in the master mould for future development and application of printing in the electronic, graphic and bio-medical field

Ding, S.

Embong, Z.

Hassan, S.

Marwah, O.M.F.

Yusof, M.S.

UTHM Institutional Repository

Improvement Inaccuracy Correlation IC Radiated Electric Fields Measurement in GTEM Cell to SAC Using A Correction Factor  King Lee Chua1, a, Mohd Zarar Mohd Jenu1, b,  Man On Wong2, c, See Hour Ying2, d 1Center for Electromagnetic Compatibility,  Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), Parit Raja, Batu Pahat, 86400 Johor, Malaysia. 2Altera Corporation (M) Sdn. Bhd. Plot 6, Bayan Lepas Technoplex,  Medan Bayan Lepas, 11900, Penang, Malaysia. achua@uthm.edu.my, bzarar@uthm.edu.my, cmowong@altera.com, dshying@altera.com   Keywords: GTEM cell, radiated emission, integrated circuit, SAC Abstract. GTEM cell appears to be a popular test facility for integrated circuits (ICs) radiated emission evaluations in the past. Since the GTEM cell is a single port test device, the GTEM measurement cannot specifically differentiate components between electric and magnetic fields. Both fields are captured as a global quantity in GTEM measurement. It therefore is a suspicion that the radiated emission measurements using GTEM cell is less precise in contrast to scanning technique i.e. near field probe scan. However, GTEM cell is a cost effective test device that provides good ambient shielding to conduct field measurement in broad frequency. The GTEM measurement usually is associated to semi-anechoic chamber (SAC) measurement. Thus, this study attempts to improve the correlation of the GTEM to SAC using a correction factor. In particular, a specific pattern was developed to replicate wide-ranging IC interconnections for the evaluations in GTEM cell and SAC. The horizontal and vertical electric fields based on the GTEM measurements were preprocessed using Matlab code before it is ready to attain the correction factor. Finally, the correction factor is employed to adjust the deviation while correlating the IC radiated electric fields of GTEM cell to semi-anechoic chamber. The results indicate a great improvement after regulating the GTEM fields with the correction factor. This implies the GTEM cell measurement is possible to achieve a good accuracy using a correction factor.  1. Introduction Modern electronic appliances extensively utilizing integrated circuits (ICs) for signal processing applications due to the benefits of smaller size and lower development cost. Today, advance process integration technology and the introduction of new packaging technology at chip scale allow the production of incredible dense integrated circuits with higher number of I/Os that can operate at exraordinary frequency. Consequently, these integrated circuits most likely become significant noise sources to cause electromagnetic interference (EMI) in electronic devices [1, 2]. This unintentional electromagnetic noise may degrade the performance on an electronic device and cause them malfunction. The electromangetic interference concerns at component level have gained great attention due to the growing demand over low emission and high immunity device towards electromagnetic disturbance, especially when engaging safety implications in automotive and consumer electronics applications [3].  In particular, the Society of Automotive Engineers has introduced standard SAE J1752/3 [4] for measuring the electromagnetic emissions from an integrated circuit in 1995. In the subsequent year the introduction of the SAE J1752/3, the International Electrotechnical Commision (IEC) published standard IEC 61967-2 [5] for similar purposes. Both standards define the evaluation of an IC electromagnetic radiation by clamping the integrated circuit test printed circuit board (PCB) to a wall port cut in the top or bottom of a tranverse electromagnetic (TEM) or widband TEM (GTEM) cell. The frequency range for the evaluation is 150 kHz to 1 GHz. These standards are widely accepted by industries and researchers to perform electromagnetic radiation from an integrated circuit.  As the IC requires supporting components for operation, the evaluation by clamping the IC test board on the cell wall is vital to seperate the radiation of the IC from its board environment. This is the main reason of the proposed measurement approach. But, the setup has limited the rotation of the test board in two dimensions across its vertical axis. Generally, the radiated emissions are based on measurement the horizontal and vertical polarization fields. The measurement by clamping the IC test board on the wall port tends to neglected the vertical polarization field which is also significant [6, 7] and should be taken into consideration in the measurements. It is therefore desirable to have an alternative method to evaluate IC radiated emissions which account both horizontal and vertical polarization fields. By performing the emission test inside GTEM cell, the unpredicted fabrication defect can be avoided. In addition, the test device can freely rotated in three orthogonal dimensions for data collection. The exploration of the IC electromagnetic behavior provides vital information for component selection and design concerns in an early product development stage. It can assist to shorthen the product development process as well as avoiding additional shielding or fieltering costs prior to compliant product EMC requirements. This paper describes the work to improve the measurement deviation between GTEM cell and semi-anechoic chamber (SAC) using correction factor. To establish the correction factor, we developed a simple pattern as general representation of IC. The pattern was utilized to execute the electric fields measurements in GTEM cell and SAC. The correction factor is obtained as a ratio SAC field measurement with respect to estimation field based on GTEM cell measurement. Then, the correction factor is taking into account to adjust the deviation on the electric fields for IC in GTEM measurements. The results after correction illustrate a promising correlation between GTEM cell and semi-anechoic chamber measurements.  2. The Concept For IC Radiated Emission Measurements in GTEM Cell GTEM cell is an enclosed and tapered transmission line that is terminating by a boardband RF load. The cell structure allows a frequency response extended beyond 1GHz. A testing volume of the cell typically defined below the inner transmission line or septum plate. For evaluating emission of an IC in the cell, the IC test board must be placing within the testing volume. The electromagnetic fields contributed by the IC will couple with the septum plate to induce voltage and current waves that propagating along the septum plate, eventually measuring by spectrum analyzer that attached to the cell port.  Ferrite beads Fig. 1 : Illustration of an evaluation radiated emission generated by IC  The setup to measure IC radiated emission in GTEM cell is shown in Fig. 1. The major concerns of the setup in Fig. 1 are unintentional disturbances contributing by the IC supporting components and its interface cables would upset accuracy of the measurement. In [6], we have presented the effectiveness to tackle these crucial matters in the setup by applying several electromagnetic compatibility (EMC) measurement approaches such as shielding, grounding and suppression using ferromagnetic material. Fig. 2 illustrates an actual setup of IC test board in the GTEM cell. The experimental works proven these techniques are useful to ensure reliable IC emission measurement in GTEM cell. The results in [6] indicate a comparative good correlation between GTEM and semi-anechoic chamber measurements. However, there still have some variations between the correlations. For enhancing agreement on the correlation values, this paper proposes a further improvement by using a correction factor.   Fig. 2 : Approaches for minimizing contribution of unintentional noises  3. Representation of IC with A Spiral Pattern Generally, each IC contains numerous wire routings for interconnections of active elements in the IC. In fact, the routing for each IC is unique, so it is difficult to be reproduced exactly same like routing in the IC. Since routing is establishing to connect all the active elements located in whatever locations in the IC, we therefore suggested the development of a spiral pattern in square as a representation of the IC. Fig. 3(a) shows the circuit utilizes to drive the spiral pattern. To avoid the used of interfacing cable, the circuit is designed to be powered by a rechargeable battery. The circuit attached with a crystal to generate a sinusoidal signal in frequency 50MHz for travelling along the spiral pattern. From Fig. 3(a), it clearly seen the most right trace, highlighted in red color is the section to be manipulated to form the spiral pattern. The Fig. 3(b) and (c) present actual PCB Grounding Suppression and shielding Shielding for the circuit. As found in the figure, the top PCB only comprises the spiral pattern but all the components are mounted at bottom PCB. A large ground plane is formed in the bottom PCB, thus the spiral pattern actually sitting on top of ground plane.   (a)   (b) (c) Fig. 3: A proposed circuit to represent IC for developing a correction factor, (a) Schematic of the test circuit, (b) Top side, (c) Bottom side  4. Determination of the Correction Factor with Equivalent IC Pattern The evaluation of the radiated fields for the equivalent pattern will be the same as explained in section 2 and Schaffner GTEM 750 is the measuring instrument. In general, the GTEM cell measurement cannot differentiate between electric and magnetic fields. Both fields are reading by spectrum analyzer as a global value in term of voltage. In this case, analytical equations are required for extracting an equivalent dipole moment to represent the pattern. This equivalent moment is deemed as equivalent radiation source to be applied for estimating horizontal and vertical electric fields at a distance away from the source. In [7], we have explained the technique acquired to estimate radiated horizontal and vertical electric fields of IC based on measurement in GTEM cell. For correlation between GTEM results with SAC results, the radiated electric fields of the pattern also evaluated in SAC using biconical antenna which is placed at a 3 m distance away from the pattern. SAC is a shielded room that considered as alternative technique to measure radiated electric fields. However, the SAC usually evaluate the radiated electric fields in far distance. The illustration for radiated electric fields test in SAC is shown in Fig. 4.  Spiral pattern Ground plane  (a)    (b) Fig. 4 : Radiated electric fields test in SAC, (a) Configuration of SAC measurement parameters; (b) Actual setup of the equivalent pattern on SAC measurement The correction factor that proposed to adjust the deviation on correlation GTEM cell and SAC defined as ratio of SAC field measurement with respect to GTEM estimation field. In particular, the GTEM estimation field and SAC field are obtained using the spiral pattern. The equation of the correction factor is given by  Correction	factor, CF SAC	measurementGTEM	estimation	ield Eqn. 1 After determine the correction factor, it is now ready to be applied to regulate the estimation of radiated electric field for IC using Eqn. 2. In this case, it supposes the application of correction Horizontal Vertical  factor has eliminated the unforeseen factors that affect the precision to correlate the GTEM estimated fields to SAC measured fields.  e	GTEM	estimation	ield  CF  GTEM	estimation	ield	for	C Eqn. 2 For application, we selected a FPGA chip as actual test device to repeat the radiated electric field in GTEM and SAC measurements. The FPGA chip is mounting on a standardized 10cm x 10cm test board designed according to the specifications in IEC 61967-1. To avoid disturbance contributing by supporting components of the FPGA chip in the measurement, the entire FPGA test board is shielded with a metallic enclosure except the FPGA chip is exposing through a window. A TFF pattern also designed to be loaded into the FPGA chip. A 50 MHz sinusoidal clock frequency was supplied to exercise the operation of the TFF pattern. Fig. 5 shows the resultants horizontal and vertical components of the radiated electric field that estimated from GTEM measurement as validated with direct measurement in SAC. The figure clearly indicates the deviation on the correlation GTEM measurement to SAC measurement be removed using the proposed correction factor. An extremely good agreement is obtained between the two fields after the correction.   (a)   (b) Fig. 5 : Comparison estimated radiated electric fields of IC before and after adjusting with correction factor to SAC measurement; (a) Horizontal component of radiated electric field; (b) Vertical component of radiated electric field 100 200 300 400 500 600 700 800 900 1000-100102030405060Frequency (MHz)Amplitude (dBuV/m)  SAC MeasurementGTEM estimation before correctionGTEM estimation after correction100 200 300 400 500 600 700 800 900 1000-100102030405060Frequency (MHz)Amplitude (dBuV/m)  SAC MeasurementGTEM estimation before correctionGTEM estimation after correction5. Conclusion This paper has presented a correction factor that applicable to adjust the difference in correlating GTEM to SAC for integrated circuit, i.e. FPGA chip. The correction factor was attained using a spiral pattern as universal representation for the complicated interconnect traces in integrated circuit. It has been shown that a relative good correlation of IC radiated electric fields can be achieved between GTEM and semi anechoic chamber measurements. However, further investigation will be conducting to examine other factor in order to improve peak amplitude between measurement and prediction results.  Acknowledgement The authors wish to thank Multimedia Development Corporation (MDeC) for the financial support and Altera Corporation (M) Sdn. Bhd. for providing FPGA test board for the research.  Reference 1. David, K. The Growing Complexity of FPGA CAD Tools. in Reconfigurable Computing and FPGA's, 2006. ReConFig 2006. IEEE International Conference on. 2006. 2. Pencek, B. Reconfigurable Application-Specific Computing: How Hybrid Computer Systems using FPGAs are Changing Signal Processing. Available from: www.industrial-embedded.com/articles/pencek/. 3. Mittra, R. Challenges in real-world Emi/Emc problems and some novel techniques for meeting them. in Electromagnetic Compatibility and 19th International Zurich Symposium on Electromagnetic Compatibility, 2008. APEMC 2008. Asia-Pacific Symposium on. 2008. 4. Measurement of Radiated Emissions from Integrated Circuits -- TEM/Wideband TEM (GTEM) Cell Method; TEM Cell (150kHz to 1 GHz), Wideband TEM Cell (150kHz to 8GHz), Jan. 2003, Soc. Autom. Eng. Standard SAE J1752-3. 5. Integrated Circuits -- Measurement of Electromagnetic Emissions, 150kHz to 1GHz -- Part 2: Measurement of Radiated Emissions - TEM Cell and Wideband TEM Cell Method, 2005, Int. Electrotech. Commiss. Standard EMC 61967-2. 6. King Lee Chua, M.Z.M.J., Man On Wong, See Hour Ying, Exploration Electromagnetic Noise Reduction for IC Electric Field Measurement and Prediction in GTEM Cell. International Journal of Engineering & Technology IJET-IJENS, April 2014. Vol. 14: p. 32-38. 7. Chua, K.-L.M.J., Mohd Zarar; Wong, Man-On; Ying, See-Hour, Radiated emissions estimation of an integrated circuit based on measurements in GTEM cell in Asia-Pacific International Symposium and Exhibition on Electromagnetic Compatibility: APEMC 2013 2013, Engineers Australia: Melbourne, Australia. p. 292-295.   

A study of printing plate mould development by using 3d printers for micro-flexographic printing process

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