Program and Abstract Book - SRON

More documents

Recommendations

Info

19 th International Symposium on Space Terahertz Technology P12-2 Simulation of THz Receiver Systems Using Hybrid Numerical Methods and Spectral Ray Tracing Technique Iraj Ehtezazi Alamdari 1 , Jian-Rong Gao 2 , Safieddin Safavi-Naeini 1 , 1- University of Waterloo, Canada, iraj@maxwell.uwaterloo.ca, safavi@maxwell.uwaterloo.ca 2- Technical University of Delft, SRON, The Netherlands, J.R.Gao@tudelft.nl In this paper the original Spectral Ray Tracing (SRT) technique is applied to calculate the radiation patterns of the antennas combined with the lens. The effects of internal reflection inside the closed volume of the lens are taken into account. SRT has been successfully applied to different kind of lens-antenna combinations and the results have good agreement with the measurement. In this paper we are comparing the results of SRT with commercial software and also we are applying the new hybrid method of SRT and MOM/FEM. In the hybrid method the field distribution around the near field of the antenna is calculated with numerical methods such as Method of Moments (MOM) and Finite Element Method (FEM) and then the effects of complex large structure surrounding the antenna on the radiation patterns of the antenna is calculated with SRT method. A second step of numerical calculation is necessary to evaluate the effects of the complex structure on the input impedance of the antenna. Because of the large size of the complex structure, MOM and FEM numerical methods are not efficient; on the other hand SRT can easily calculate the fields in complex large structures. The effect of the lens on input impedance of the antenna will be studied using the hybrid methods mentioned above. The internal reflections inside the lens will modify both the radiation patterns and the input impedance of the antenna. For the antenna design, two kinds of antennas will be studied for application in THz receiver systems: twin slot antenna and spiral antenna. The radiation patterns will be calculated with FEM & MOM along with the input impedance of the antennas for the near field of the antennas. We are using commercial software HFSS for Finite Element Method and FEKO for Method of Moments and different kinds of hybrid methods like MOM-GTD and MOM-PTD. The hybrid methods MOM-SRT and FEM-SRT are new methods in these aspects. 160
19 th International Symposium on Space Terahertz Technology P12-3 Development of a 385-500 GHz Orthomode Transducer (OMT) Mamoru Kamikura 1,2 , Masato Naruse 1,2 , Shin’ichiro Asayama 2 , Naohisa Satou 2 , Wenlei Shan 3 , and Yutaro Sekimoto 1,2 1 Department of Astronomy, School of Science, the University of Tokyo 2 Advanced Technology Center and ALMA-J project office National Astronomical Observatory of Japan, National Institutes of Natural Sciences 3 Purple Mountain Observatory, Chinese Academy of Sciences We present the design and evaluations of an orthomode transducer (OMT) for ALMA Band 8 (385-500 GHz) [1]. An OMT is a passive waveguide polarization diplexer that separates the signal received by a feed horn into its two orthogonal linearly-polarized components. Because of the difficulty of fabrication, an OMT has not been developed at frequencies above 320 GHz [2]. The design of the Band 8 OMT was similar to that of the ALMA Band 4 (125-163 GHz) OMT [3], which is based on an OMT with a Bφifot junction and a double ridged waveguide [4]. In submillimeter wavelengths mechanical tolerance becomes very severe, so we simulated effects of mechanical errors on the S-parameters of the OMT. The design is so robust that mechanical errors of 10 μm do not affect the performance of the OMT. The polarization isolation and the transmission loss of the Band 8 OMT were evaluated. The polarization isolation of the OMT measured to be larger than 25 dB with quasi-optical measurements. The transmission loss of the OMT at 4 K was determined to be 0.4 dB from noise measurements with a DSB mixer. References [1] Y. Sekimoto et al., this conference. [2] E.J. Wollack and W. Grammer, “Symmetric Waveguide Orthomode Junction,” 14 th ISSTT, pp. 169-176, 2003. [3] S. Asayama et al., 2008, in preparation. [4] G. Moorey, R. Bolton, A. Dunning, R. Gough, H. Kanoniuk, and L. Reilly, “A 77-117 GHz Cryogenically Cooled Receiver for Radioastronomy,” Proc. of Workshop on the Applications of Radio Science, 2006. 161
Page 1 and 2:
ISSTT 2008 19 th International Symp
Page 3 and 4:
19 th International Symposium on Sp
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112: 19 th International Symposium on Sp
Page 161: 19 th International Symposium on Sp
show all

Program and Abstract Book - SRON

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?