A modified boundary surface 

between the two domains in the hybrid 

FEM-FDTD technique is presented. This 

permits a heterogeneous surface to be 

imposed, allowing selected parts to be 

represented as being conducting or 

non-conducting. This enables a reduced 

surface size to be used in cases where an 

antenna is above a conducting plane, as well 

as facilitating a range of other practical 

scenarios. Examples presented show stable 

results and good agreement with published

data

Abd-Alhameed, R. A.

Alias, R.

Excell, P. S.

UTHM Institutional Repository

PEMBANGUNAN KERANGKA MAKMAL FIQH DI UNIVERSITI AWAM MALAYSIA WAN AINAA MARDHIAH BINTI WAN ZAHARI Tesis ini dikemukakan sebagai memenuhi syarat penganugerahan Ijwah Sarjana Sains secara Penyelidikan Fakulti Sains Teknologi dan Pembangunan Insan Universiti Tun Hussein Onn Malaysia OGOS 2015 ABSTRAK Kajian ini bertujuan untuk membina kerangka Makmal Fiqh di Universiti Awam Malaysia. Objektif yang ingin dicapai adalah untuk mengenal pasti kaedah pembelajaran Fiqh berasaskan pengalaman yang terdapat di Universiti Awam Malaysia dan juga mengenal pasti keperluan kerangka Makmal Fiqh berinovatif berasaskan konsep Fiqh Islam setemsnya rnencadangkan kerangka Makmal Fiqh berinovatif untuk subjek Fiqh Ibadah. Kajian ini melibatkan pelajar jurusan Fiqh dan Syariah di empat buah universiti awam; Universiti Sains Islam Malaysia (USIM), Universiti Kebangsaan Malaysia 0, Universiti Malaya (UM) dan Universiti Islam Antarabangsa Malaysia (UIAM). Kajian ini menggunakan gabungan antara pendekatan kualitatif dan kuantitatif, Pendekatan kualitatif melibatkan penggunaan kaedah temubual yang dijalankan kepada 10 orang pakar dalam bidang Fiqh dan Syariah. Manakala pendekatan kuantitatif pula adalah dengan menggunakan kaedah tinjauan soal selidik kepada para pelajar jurusan Fiqh dan Syariah di USIM, UKM, UM dan UIAM. Kedua-dua kaedah fi digunakan untuk mengetahui pandangan responden terhadap cadangan penubuhan Makmal Fiqh untuk subjek Fiqh Ibadah di Universiti Awam Malaysia. Hasil data temubual dianalisis menggunakan analisis kandungan (content analysis). Manakala data tinjauan soal selidik pula dianalisis menggunakan perisian Statistical Package for Social Science (SPSS). Hasil kajian utarna menunjukkan 1 00% responden bersetuju dengan cadangan penubuhan Makmal Fiqh. Hasil dapatan adalah pembinaan 12 kriteria yang perlu ada pada Makmal Fiqh serta 3 cadangan langkah berjaga-jaga yang perlu diambil dalam Makmal Fiqh. Selain itu, 15 keperluan dan peralatan yang diperlukan dalam Makmal Fiqh dihasilkan di samping 6 ciri-ciri yang dapat membezakan Makmal Fiqh dengan makmal-makmal pengaj man dan pembelajaran (P&P) yang lain turut dihasilkan. ABSTRACT This research is done to develop the Makrnal Feqh's framework in Malaysian Public University. Hence, the objectives are to identify the method of experiential learning for the Feqh subject practiced in Malaysian Public University and also to know the needs for this Makmal Feqh and to suggest the best h e w o r k  of Makmal Feqh. This research involves the students fiom USIM, UKM, UM and UIA. The methodology for this research is through the qualitative and quantitative approaches. The qualitative approach is used by having interview with 10 experts in Feqh and Shariah. The second approach is used by conducting the survey method to the Feqh and Shariah students. These two approaches are done to know the views and suggestions about the Makmal Feqh in the Malaysian High Education Institution. While the result fiom the interview is analysed using content analysis method. While result from the survey is analysed using Statistical Package for Social Science .' (SPSS}. The main result showed that 100% respondents agreed with the suggestion of Makmal Feqh. The result of this research is to know the 12 criteria of Makrnal Feqh and also the needs that should exist in the Makrnal Feqh. The uniqueness of Makmal Feqh from the other teaching and learning laboratories is also shown. The finding of this research showed 100% respondents agreed with the suggestion for Makmal Feqh. The findings are for developing 12 criterias that should be have for Makmal Feqh, 3 suggestion for safety precaution that should be taken for Makmal Feqh, 15 needs and tools that should be prepared for Makmal Feqh and 6 criterias distinguish Makmal Feqh from the other laboratories. Ab. Halim, Tarnuri (2007). Amalan Pengajaran Gum Pendidikan Islam Dalam Membangunkan Masyarakat Islam Hadhari. Penerbit Univasiti Malaya. Abd. Rahirn, R. A., Ismail, P., Mohamad, S., Dahlal, N. H. & Nordin, B. (2008). Paradigma Pemikiran Pengajian IsIam Semasa: Analisis Pedagogi, Journal of Ethics, Legal and Governance, 4, 13-34. Abd. Rahim, R. A., Omar, L., Abd Kadir, N. A. & Dahlal, N. H. (2009). Kemahiran Insaniah Di Institusi Pengajian Tinggi Awam Islam Malaysia Dan Indonesia: Satu Analisis Perbandingan. Journal of Southeast Asian Studies, 14. Abdul Rahman, N. N., Ali, A. K., Ramli, R. & Ismail, M. S. (2008). The Teaching And ,' Learning Of Usul A1 fiqh In Public Universities In Malaysia: Reality And Challenges, Jurnal Syariah, 16, 523-536. Abdul Rahman, N. N., Jamaludin, M. A. & Ramli, M. A (2013). Pendekatan Wasatiyyah (Sederhana) Dalam Pembinaan Fiqh Kontemporari. Seminar Isu-Isu Kontemporari Dadam Mazhab Shaj'i. Universiti Malaya. p. 139- 1 55. Abdullah, A. B., Ramli, M. A., Jamaludin, M. A., Marinsah, S. A. & Mohd Nor, M. R. (20 13). Postmodemism Approach in Islamic Jurisprudence (Fiqh). Middle-East Journal of ScientiJic Research 13 (I), p. 3 3-40. Abonyi, Okechukwu (2013). Effects of Experiential Learning Strategy on Secondary School Students' Achievement In BioIogy Conference. World Conference on Science and Technology Education. Ebonyi State University. 

A conducting domain surface boundary applied to hybrid FEM-FDTD Electromagnetic models

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Dalam kajian ini, soal selidik telah diedarkan kepada 100 orang pelajar saijana

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kajian telah dianalisis menggunakan perisian Statistical Package for Social Sciences

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web INCAMPNET sesuai dalam mengatasi masalah pencarian maklumat

Abu Zakaria, Nik Reduan

International Journal of Advanced Computer Science, Vol. 2, No. 10, Pp. 382-384, Oct., 2012.     Manuscript  Received: 7,Dec., 2011 Revised: 7,May, 2012 Accepted: 8, Jul., 2012  Published:  15,Nov., 2012   Keywords  HYBRID  FEM-FDTD, ELE. MAG. MODELS   Abstract A modified boundary surface between the two domains in the hybrid FEM-FDTD technique is presented. This permits a heterogeneous surface to be imposed, allowing selected parts to be represented as being conducting or non-conducting. This enables a reduced surface size to be used in cases where an antenna is above a conducting plane, as well as facilitating a range of other practical scenarios. Examples presented show stable results and good agreement with published data.  1. Introduction and Method The finite element method (FEM) is widely used in computation of unbounded static and quasi-static electric and magnetic fields at DC and low frequencies, and for enclosed systems (cavities etc) at high frequencies. However, there have been problems in applying the method to high-frequency open-field (radiation and scattering) problems due to the relatively large size of the computational tasks that result. The finite-difference time-domain (FDTD) scheme is very popular for electromagnetic modeling because of its simplicity and efficiency. One drawback of FDTD is the staircase approximation of oblique boundaries, which often gives poor accuracy. The finite-element method (FEM) allows good approximations of complex boundaries and with edge elements it performs well for Maxwell’s equations [1]. An obvious compromise is a hybrid that applies FDTD in large volumes, combined with FEM around regions with complex structure: the FEM may be applied in frequency domain to achieve very efficient solutions. Previously attempted hybrids of this type have only used time-domain FEM [2] and some have shown late-time instabilities [3,4]. The coupling between the hybridised methods is computed by using the equivalence-principle (EP) theorem. The objects in the different domains are not physically connected but need only be separated by a small distance, sufficient to permit the surface on which the equivalence principle is enforced to be located between them.  In this paper, a modified EP surface in which one or more faces are replaced by a conducting surface was                                                         R Alias, R A Abd-Alhameed and P S Excell are with Telecommunication Research Center, Bradford University, Bradford, BD7 1DP, United Kingdom. Email Address:( ozlan@uthm.edu.my, r. a.abd@bradford.ac.uk ) investigated (see Fig. 1). In this modification, the conducting surface can be extended beyond the size of the EP surface, for example a handset box for a mobile phone, where only the antenna part is within the EP surface. The Inverted F-Antenna (IFA) was chosen for evaluation purposes since it is a common mobile phone design. The antenna, including a finite ground plane, was modelled by using a standard FEM software package [5]. In the first test, the EP surface boundary was chosen to reach to the edges of the finite ground plane representing the adjacent surface of the phone body (see Fig. 1a) and then the size of the EP surface was reduced and the antenna performance was again predicted, with and without the presence of an arbitrary conducting-sheet scatterer (see Fig. 1b), inserted below the ‘ground plane’. Outside the FEM domain, the rest of the problem space was inserted in an FDTD region. The procedure can be extended to two or more conducting surfaces partially coinciding with the EP surface. Due to the differing structures of FEM (normally non-uniform tetrahedral meshing) and FDTD (normally uniform rectangular cell distributions), a support program was written to link the field points that exist on either side of the EP surface.  2. Simulation and Results  A program was written to simulate the details presented in the previous section. The operating frequency was chosen as 1800 MHz and the handset dimensions (finite ground) were 5cm x 8cm. The antenna was designed with minimum return loss of 10dB and 9% relative bandwidth at 1800MHz. The complete FEM problem space for the examples presented stretched well beyond the EP surfaces and was of size 12cm x 9cm x 4cm, with its lower surface coincident with the finite ground plane. Outside the metallic plane, the lower surface of the FEM model used the low reflecting boundary formulation [5]. The antenna was excited by a magnetic frill through a coaxial cable of radius 2.5-mm. The FDTD cell size and the time step were 2.5mm and 3.375ps respectively. The number of the FDTD PML (perfectly matched layer) cells was 6.  Example 1: The total field (for 1 watt input power) as seen 1cm underneath the centre of the ground plane, on a line parallel to the x-axis, was examined; the scatterer plate was absent. The EP surfaces were considered at the edges of the A CONDUCTING DOMAIN SURFACE BOUNDARY APPLIED TO HYBRID FEM-FDTD ELECTROMAGNETIC MODELS R. Alias, R.A. Abd-Alhameed & P.S. Excell R. Alias et al.: A CONDUCTING DOMAIN SURFACE BOUNDARY APPLIED TO HYBRID FEM-FDTD ELECTROMAGNETIC MODELS. International Journal Publishers Group (IJPG) © 383  handset (Fig. 1a) and closer to the antenna (Fig. 1b). A comparison between the two geometries, and with the pure MoM [6] is shown in Fig. 2. The FDTD problem space dimension was 54 x 54 x 38 cells. The EP surface sizes for Figs 1a and 1b were 5cm x 8cm x 3cm (equivalent to 32 x 20 x 12 cells inside the FDTD method) and 3cm x 4cm x 3cm (equivalent to 12 x 16 x 12 cells inside FDTD) respectively. The results show good agreement for all proposed equivalent surfaces. The results also show that the difference between the total field and the scattered fields in the case of the FEM/FDTD hybrid method was 25 to 30 dB: this is in accord with expectations. However, the computer memory needed for the field points on the surface boundary with the modified equivalent surface (Fig. 1b) was reduced by 70% compared to the one in Fig. 1a and this directly contributed to reduce the execution time in updating the boundary difference equation inside the FDTD method.   (a)  (b)  Fig. 1 Antenna structure with EP surfaces, either reaching to the edges of the ground plane (a), or enclosing a reduced small volume (b). The lower scatterer plate was introduced in later tests (Fig. 3).  Example 2: In this example, a scatterer was considered underneath the handset as shown in Fig. 1b. The scatterer was a conducting surface of size 5cm x 6cm which is equivalent to 20 x 24 cells inside the FDTD method. The variations of the input impedance for different distances between the handset and the scatterer were computed and are shown in Fig. 3. The computed results were in acceptable agreement with those calculated from pure MoM [6].   Fig. 2 The total field 1cm underneath the longitudinal centre line of the ground plane (no scatterer present).   Fig. 3 The variations of the input impedance versus distance between the ground plane and the scatterer  3. CONCLUSIONS A hybridisation technique between the FEM and FDTD has been presented. An equivalence-principle surface, including a partial conducting surface, was successfully implemented through the boundary that coupled the two methods. A reduced-size EP surface has been presented and was found sufficient to predict the antenna performance with and without the presence of a nearby scatterer. This saved approximately 70% of the required memory locations of the field points between the two domains and also accelerated the updating boundary equations inside the  International Journal of Advanced Computer Science, Vol. 2, No. 10, Pp. 382-384, Oct., 2012.  International Journal Publishers Group (IJPG) © 384  FDTD method. The results are stable and show good agreement between the different techniques.   References [1] J. Jin, The Finite Element Method in Electromagnetics, New York: John Wiley & Sons Inc, 1993. [2] T. Rylander and A. Bondeson: ‘Application of Stable FEM-FDTD Hybrid to Scattering Problems’, IEEE Transactions on Antennas and Propagation, Vol. 50, No. 2, Feb. 2002, pp. 141-144. [3] R.B. Wu and T. Itoh, “Hybrid finite-difference time-domain modeling of curved surfaces using tetrahedral edge elements,” IEEE Trans. Antennas Propagat., vol. 45, pp. 1302–1309, Aug. 1997. [4] A. Monorchio and R. Mittra, “A hybrid finite-element finite-difference time-domain (FE/FDTD) technique for solving complex electromagnetic problems,” IEEE Microwave Guided Wave Lett., vol. 8, pp. 93–95, Feb. 1998. [5] Comsol AB, FEMLAB, Electromagnetic Software Version 3.0, Comsol Ltd., Jan. 2004. [6] Mangoud, M.A., Abd-Alhameed, R.A. and Excell, P.S.: 'Simulation of human interaction with mobile telephones using hybrid techniques over coupled domains', IEEE Trans. on Microwave Theory and Techniques, vol. 48, No. 11, Nov. 2000, pp. 2014-2021.                                                       

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A conducting domain surface boundary applied to hybrid FEM-FDTD Electromagnetic Models

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A conducting domain surface boundary applied to hybrid FEM-FDTD Electromagnetic models

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