F. Arndt

Universität Bremen, Bremen, Bremen, Germany

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Publications (177)153.51 Total impact

  • F. Arndt
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    ABSTRACT: The EM CAD tool WASP-NET is applied for the direct EM optimization of reflector antennas and slot-arrays including feed networks. Based on an advanced multi-solver EM CAD technology, hybridizing mode-matching (MM) / finite-element (FE) / method-of-moment (MoM) / finite-element-boundary-integral (FE-BI) / physical theory of diffraction (PTD) methods, typical calculation times for one optimization iteration are merely in the order of a few seconds (e.g. for body-of-revolution (BOR) type of antennas) up to a few hundreds of seconds (e.g. for large dual-offset reflector antennas or large slot-arrays) per frequency point on a standard quad-core PC. This high calculation speed allows to meet desired specifications by direct EM optimization within short design cycles. Mutual coupling effects are rigorously taken into account. Direct EM optimizations of the entire structure immediately together with corresponding feed and feed networks yield complete, accurate design solutions without the need of post assembly re-adjustments.
    2013 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting; 07/2013
  • F. Arndt
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    ABSTRACT: WASP-NET's advanced multi-solver hybrid domain (de)composition technique, which is uniquely based on six solvers - mode-matching (MM) / finite-element (FE) / method-of-moment (MoM) / finite-difference (FD) / finite-element boundary-integral (FE-BI) / physical theory of diffraction (PTD) -, fully utilizes the efficiency and flexibility advantages of the involved methods. The CAD tool's recent advances include a graphical 3D structure editor for arbitrary user-defined structures parametrized by variables, 3D structure import via standard data formats, and the inclusion of efficient MoM techniques for, e.g., radar cross-section (RCS) investigations, fast optimizations of large antenna arrays, and the inclusion of lossy dielectrics and tensor materials. The high calculation speed and 3D flexibility will be demonstrated at typical examples that are relevant for the antenna engineer, e.g., arbitrarily shaped ortho-mode-transducers (OMTs), shaped reflector antennas with layered, lossy radomes, and slot arrays.
    Antennas and Propagation Society International Symposium (APSURSI), 2012 IEEE; 01/2012
  • F. Arndt
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    ABSTRACT: WASP-NET's unique hybrid CAD approach comprising mode-matching (MM) / finite-element (FE ) / method-of-moment (MoM) / finite-difference (FD) techniques fully exploits the specific efficiency and flexibility advantages of the involved main EM methods. Divergence-conforming higher-order vector basis functions increase the performance of MoM algorithms; dielectric materials are effectively taken into account by the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) formulation; large antenna arrays are effectively handled by the adaptive integral (AIM) or multi-level fast multi-pole (MLFMM) methods. Recent extensions include an efficient hybrid finite-element / boundary integral (FE-BI) solver for general 3D structures, and a MoM / PTD solver for large reflector antennas. The high efficiency of the CAD software will be demonstrated at some typical examples relevant for the antenna design engineer, such as compact filters, polarizer ortho-mode transducers (OMTs), lens horn antennas, reflector antennas with shaped sub-reflectors, large reflector antennas, and slot arrays.
    01/2011; DOI:10.1109/APS.2011.5997088
  • Fritz Arndt
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    ABSTRACT: WASP-NET's hybrid CAD approach - based on about thirty years of fundamental research in computational electromagnetics (EM) - comprises mode-matching (MM) / finite-element (FE) / method-of-moment (MoM) / finite- difference (FD) techniques, and, hence, fully exploits the specific efficiency and accuracy advantages of all involved basic EM methods. Recent advances include a fast hybrid finite-element / boundary-integral (FE-BI) solver for general 3D structures, which provides full 3D flexibility for involving user-defined and imported 3D structures, and a MoM / physical theory of diffraction (PTD) solver for calculating large antennas. The high importance of fundamental, broad-band research in computational electromagnetics for the development of an efficient, accurate and flexible software "product" is illustrated by a short review of some of the corresponding development steps. A few typical application examples demonstrate the efficiency advantages of this hybrid 3D EM CAD approach, where "hybrid" can be interpreted in the double-sense: Incorporating all fundamental EM methods as well as successfully merging (fundamental) science and (CAD) product.
  • Fritz Arndt
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    ABSTRACT: In this article we will briefly report on recent advances of this hybrid CAD approach, which is characterized, in particular, by a further breakthrough in EM design and optimization speed. The significant importance for the IEEE MTT Society community is that, in this way, direct, full-wave EMdesign and optimization of advanced microwave structures and antennas can be performed within shorter design cycles. Representative application examples of industrial microwave devices/antennas will demonstrate that EM simulation times can be reduced on standard PCs (without additional hardware acceleration tools) now typically to a few seconds. Appropriate synthesis wizards provide good starting values for subsequent EM optimizations. Available measurement data verify the high accuracy of the presented hybrid EM technique.
    IEEE Microwave Magazine 01/2009; DOI:10.1109/MMM.2008.929619 · 1.67 Impact Factor
  • V. Catina, F. Arndt
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    ABSTRACT: For protecting antennas from environmental effects, and preserving aerodynamic profiles of objects with antennas, dielectric radomes are used already for a long time [1]. The presence of radomes, which commonly have different shapes, cf. e.g. [2], can significantly affect the radiation characteristics of corresponding antennas, and, hence, their analysis has found much attention in the recent past. For aperture antennas with radomes, cf. schematic sketch in Fig. 1 [3], many different techniques have been applied so far, such as ray optics [4], equivalence principles with image theory [5], integral equation (IE) methods for 2D problems [6], hybrid physical optics-method of moments (PO-MoM) techniques [3], and the finite-difference time-domain (FD-TD) method [7]. Approximate methods can lead to accuracy problems, 3D solvers can be too time consuming for desirable optimizations.
    Antennas and Propagation Society International Symposium, 2008. AP-S 2008. IEEE; 08/2008
  • F. Arndt, V. Catina, J. Brandt
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    ABSTRACT: The paper presents an overview on recent progress in the application of hybrid mode-matching (MM) / finite-element (FE) / method-of-moment (MoM) techniques for the rigorous, fast computer-aided-design (CAD) and optimization of waveguide feed components and antennas. Advanced aspects include the application of the PMCHWT (Poggio, Miller, Chang, Harrington, Wu, Tsai) method for dielectric loaded structures, the utilization of higher-order vector basis functions, and the adaptive integral method (AIM) for large arrays. The employed divergence-conforming basis functions, which have hitherto mostly been applied for scattering and microstrip antenna problems, achieve - together with curvilinear triangles for adequately modelling of curved surfaces - high efficiency, accuracy and flexibility. The versatility of the reported techniques are demonstrated at typical examples of practical importance, including dielectric loaded structures and large slot arrays.
    Antennas and Propagation, 2007. EuCAP 2007. The Second European Conference on; 12/2007
  • V. Catina, F. Arndt
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    ABSTRACT: Dielectric loaded horns have found widespread application due to their inherent potential of having features similar to corrugated horns, while being less frequency sensitive and more easily to be manufactured, in particular for higher frequencies. In this paper, we follow a different MoM approach by using divergence-conforming higher-order vector basis functions, which have mostly been employed for scattering and microstrip antenna problems so far. Moreover, curved surfaces is modeled using curvilinear triangles in order to minimize geometrical modeling inaccuracies. The advantages include higher efficiency, accuracy and flexibility. For solving the given problem, the electric field integral equation (EFIE) is combined with the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) formulation. The combined formulation is named EFIE-PMCHWT method underlining the fact that the EFIE is applied to model the fields on the aperture and conductor surfaces, and the PMCHWT method is utilized for modelling dielectric structures inside the waveguide housing.
    Antennas and Propagation Society International Symposium, 2007 IEEE; 07/2007
  • V. Catina, F. Arndt, J. Brandt
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    ABSTRACT: A combined electric field integral (EFIE) Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) surface integral equation technique is presented, in which divergence-conforming higher order vector basis functions are applied. Curved surfaces are modeled using curvilinear triangles in order to minimize geometrical modeling inaccuracies. Conforming vector bases provide appropriate continuity at material interfaces and allow for imposing boundary conditions on unknown fields or currents. The advantage of the proposed method against existing approaches is its higher efficiency and flexibility. The versatility and accuracy of the method are verified at typical filter examples by comparison with reference results.
    Microwave Symposium, 2007. IEEE/MTT-S International; 07/2007
  • F. Arndt, V. Catina, J. Brandt
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    ABSTRACT: The paper describes the application of efficient hybrid mode-matching (MM)/finite-element (FE)/method-of-moment (MoM) techniques for the rigorous, fast computer-aided-design (CAD) and optimization of waveguide components and antennas. Advanced aspects involve a surface integral equation MoM technique for the design of arbitrarily shaped three-dimensional waveguide elements including dielectric structures, and the application of the adaptive integral method (AIM) for the efficient calculation of large arrays. The described hybrid techniques combine advantageously the efficiency of the MM method with the flexibility of FE and MoM methods. Typical application examples demonstrate the versatility of the presented hybrid techniques; their accuracy and efficiency is verified by available measured results.
    Microwave Conference, 2006. APMC 2006. Asia-Pacific; 01/2007
  • I. Rullhusen, F. Arndt
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    ABSTRACT: A method-of-moment (MoM) technique is presented for the rigorous analysis of multi-layer reflectarrays using microstrip patch elements of variable size. The electric field integral equation (EFIE) in mixed potential form is discretized using Rao-Wilton-Glisson or rectangular basis functions, respectively. The required Green's functions are evaluated by Felsen's equivalent transmission line method. For the efficient MoM computation, the adaptive integral method (AIM) is applied.
    Antennas and Propagation, 2006. EuCAP 2006. First European Conference on; 12/2006
  • V. Catina, F. Arndt, J. Brandt
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    ABSTRACT: A combined electric field integral (EFIE) Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) surface integral equation technique is presented, in which exclusively Rao-Wilton-Glisson (RWG) functions are used for basis functions. This yields the accurate analysis of coax-fed dielectric resonator filters. The advantage of the proposed method against existing approaches is its higher efficiency and flexibility. The versatility and accuracy of the method are verified by comparison with measured results
    Microwave Conference, 2006. 36th European; 10/2006
  • V. Catina, F. Arndt
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    ABSTRACT: This paper presents a surface integral method for the rigorous analysis of edge-slot arrays of finite extension. The free space Green's function provides the desired flexibility. The numerical solution by the method-of-moments (MoM) allows the convenient calculation of the antenna pattern and of the generalized admittance matrix at the waveguide ports including higher-order modes for the intended further combination with fast hybrid mode-matching/finite-element (MM/FE) building blocks. The flexibility and accuracy of the method is verified by available reference results and measurements
    Antennas and Propagation Society International Symposium 2006, IEEE; 08/2006
  • F. Arndt, J. Brandt
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    ABSTRACT: A hybrid mode-matching/finite-element (MM/FE) method is described for the rigorous CAD and optimization of ridged waveguide filters and diplexers appropriate for low-temperature cofired ceramic (LTCC) fabrication techniques. The advantage of the proposed method against existing approaches is its high efficiency while maintaining the flexible solution for arbitrary cross-sections. A new ridged waveguide bi-furcation element achieves the convenient divider-type diplexer combination. The accuracy of the presented method is verified by available reference measurements. Its efficiency and flexibility is demonstrated by typical examples.
    Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings; 01/2006
  • V. Catina, F. Arndt, J. Brandt
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    ABSTRACT: A surface integral-equation method is combined with the mode-matching technique for the rigorous efficient analysis of waveguide filters containing arbitrarily shaped dielectric posts in arbitrary waveguide housings. The advantage of the proposed method against existing approaches is its high flexibility for calculating structures being not restricted by specific canonical shapes. A locally refined adaptive triangular surface mesh, together with the application of Rao-Wilton-Glisson and aperture eigenfunctions, respectively, for basis functions, achieves reliable modeling. The accuracy of the presented method is verified by available measurements.
    IEEE Transactions on Microwave Theory and Techniques 12/2005; DOI:10.1109/TMTT.2005.857343 · 2.94 Impact Factor
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    ABSTRACT: A hybrid mode-matching (MM)/method-of-moment (MoM) technique is presented for the rigorous analysis of the six-port junction of a conical circular waveguide with four side-coupled rectangular waveguides. The effects of the cone and of aperture curvature are rigorously taken into account. The advantage of the conical structure in comparison with its cylindrical counterpart includes achieving additional design potential, which can be applied e.g. for ortho-mode transducers (OMTs) of improved performance. The accuracy and efficiency of the method are verified by comparison with reference values.
    Microwave Conference, 2005 European; 11/2005
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    V. Catina, F. Arndt
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    ABSTRACT: Dielectric loaded horns have found widespread application due to their many attractive features. We present a surface integral method for the rigorous analysis of horns containing arbitrarily shaped dielectric structures and a waveguide aperture. The method is based on the PMCHWT formulation (named after Poggio, Miller, Chang, Harrington, Wu, and Tsai) (Chu, Y. et al., IEEE Trans. Antennas Propag., vol.AP-51, p.2837-44, 2003), which has hitherto been restricted to scattering problems. The numerical solution by the method-of-moments (MoM) allows the efficient calculation of the antenna pattern and of the generalized admittance matrix at the waveguide port, including higher-order modes for the intended further combination with fast hybrid MM/FE (mode-matching finite element) building blocks (Arndt, F. et al., IEEE Trans. Microwave Theory and Tech., vol.MTT-52, p.292-305, 2004.). The efficiency and accuracy of the method is verified by available measurements.
    Antennas and Propagation Society International Symposium, 2005 IEEE; 08/2005
  • V. Catina, F. Arndt, J. Brandt
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    ABSTRACT: A surface integral equation method is presented for the rigorous analysis of arbitrarily shaped dielectric posts in arbitrary waveguide housings. The advantage of the proposed method upon existing approaches is its high flexibility for calculating structures being not restricted by specific canonical shapes. A locally refined adaptive triangular surface mesh together with the application of Rao-Wilton-Glisson (RWG) and aperture eigenfunctions, respectively, for basis functions achieve the reliable modeling. The efficiency and accuracy of the presented method is verified by available reference results and measurements.
    Microwave Symposium Digest, 2005 IEEE MTT-S International; 07/2005
  • F. Arndt
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    ABSTRACT: For original article by W. Steyn and P. Meyer see ibid., vol.52, no.6, p.1622-5, June 2004.
    IEEE Transactions on Microwave Theory and Techniques 02/2005; DOI:10.1109/TMTT.2004.839953 · 2.94 Impact Factor
  • F. Arndt, V. Catina, J. Brandt
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    ABSTRACT: First Page of the Article
    Microwave Conference, 2004. 34th European; 11/2004