A novel diffraction lens quasi-optical monopulse antenna/feed is proposed and analyzed using finite-difference time-domain (FDTD) method. The structure consists of diffraction lenses, a quasi-optical sum- difference network, matching lenses and horns connecting waveguide. This antenna structure is novel, low-loss and compact and may be designed to be polarization-independent. Owing to its low absorptive loss and relative easy for manufacturing, this monopulse antenna/feed structure is suitable for millimeter wave and submillimeter wave application. The parameters of the structure are selected to some extent to get better performance. Calculation results are presented to show its properties.

A design method for diffractive/refractive dielectric lens antennas working at millimeter wave band is presented in this paper. One surface of this kind of lens antenna is refractive and the other is diffractive. The refractive surface is used to control the amplitude distribution of the electromagnetic wave and the diffractive surface is used to adjust the phase distribution of the electromagnetic wave. The side lobe level of this kind of lens antenna is low due to the proper distribution of the field amplitude controlled by the refractive surface, and the thickness of the lens is very thin due to the use of the diffractive surface. Two design examples of the diffractive/refractive lens antenna are given, and their radiation patterns (fed with the corrugated horns) are computed using axially symmetric FDTD algorithm and presented in this paper.

In this article, an improved iterative arithmetic of the symmetric successive over-relaxation preconditioning biconjugate-gradient algorithm (ISSOR-PBCG) is utilized to solve the 3D edge FEM equations derived from the time-harmonic electromagnetic-field boundary value problems. Several typical structures have been analyzed, and the computation time is compared with that of other algorithms such as biconjugate-gradient (BCG) algorithm and the conventional symmetric successive over-relaxation preconditioning biconjugate-gradient algorithm (SSOR-PBCG). The CPU time saved using the ISSOR-PBCG algorithm is nearly 27% and 65.5%, as compared with that using the SSOR-PBCG and the BCG algorithm. It can be seen that the ISSOR-PBCG algorithm is efficient for edge FEM equation sets derived from large-scale time-harmonic electromagnetic-field problems.

A waveguide magic tee at W band is analyzed exactly and developed. The analysis approach is a combination of the mode expansion method and finite element method,whic h is based on the weak form of Helmholtz equation. Mode expansion instead of PML (Perfectly Matched Layers) is used to truncate the computing space of finite element. A magic tee at W band (75∼110 GHz) with the structure,whic h is easy for manufacture,is developed. Calculated results are presented and compared to those in experiments. Agreement has been observed. A sensitivity analysis is carried out, which shows the influence of the tolerance of manufacture on the performance of the magic tee. And the power carrying capacity of the designed magic tee is also evaluated.

In this paper, focal field of reverse-microscope imaging system at millimeter wavelengths is analyzed with ray-tracing method and Stratton-Chu vector diffraction integral formula. Calculations have been compared with experiments and agreement is found. Lens profile is optimized to reduce aberrations and extend field-of-view of the imaging system. The numerical results are presented to show the field distribution of the optimized imaging system.