A millimeter-wave radar receiver using a z-cut LiNbO3 optical modulator with orthogonal-gap-embedded patch-antennas on a low-k dielectric material is proposed. A millimeter-wave from a reflected radar signal can be received by the patch-antennas and converted directly to a lightwave through electro-optic modulation. A low-k dielectric material is used as a substrate for improving antenna gain. Additionally, an interaction length between millimeter-wave and lightwave electric fields becomes long. As a result, large modulation efficiency can be obtained, which is proportional to sensitivity of the millimeter-wave radar receiver. Optical millimeter-wave radar beam-forming can be obtained using the proposed device with meandering-gaps for controlling interaction between millimeter-wave and lightwave electric fields in electro-optic modulation. Analysis and experimentally demonstration of the proposed device are discussed and reported for 40GHz millimeter-wave bands. Optical millimeter-wave radar beam-forming in 2-D is also discussed.

This paper proposes reflection and transmission control panels using artificially designed materials. As the artificially designed material, finite- and infinite-length metal wire array sheets are used here. Laminated structures consisting of the metal wire array sheets and dielectric material are proposed. Reflection and transmission characteristics of these structures can be controlled by changing the metal wire parameters such as wire length, spacing gaps between the wires, and the dielectric material's thickness and relative permittivity. The reflection and transmission characteristics of the laminated structures are evaluated by measurements in free space and by transmission line theory.

The metallic waveguide is one of many effective media for millimeter- and submillimeter-waves because of the advantage of its low-loss nature. This paper describes the fabrication method of PTFE-filled waveguide components with the use of the SR (synchrotron radiation) direct etching process of PTFE, sputter deposition of metal, and electroplating. PTFE is known as a difficult material to process with high precision. However, it has been reported that PTFE microstructures can be fabricated by the direct exposure to SR. First, an iris-coupled waveguide BPF with 5-stage Chebyshev response is designed and fabricated for the Q-band. It is demonstrated that the present process is applicable for the fabrication of the practical components inclusive of narrow patterns. Then, a cruciform 3 dB coupler with air-filled posts is designed and fabricated for the Q-band. Directivity and matched state of the coupler can be realized by “holes” in the dielectric material. The measurement results are also shown.

Near-field imaging has been intensively investigated to observe the shape and the physical properties of objects, aiming at wide applications in the areas of science and engineering. In this research, by using 60 GHz band waveguide-type microscopic aperture probe, the characteristics of the near-field imaging in transmission mode have been studied by simulation and experiment. The probe is made of a WR-15 rectangular waveguide with end-shielded metal plate and a 0.5 mm-diameter aperture. In the simulation, at first, the electric field distribution at the aperture, at the rear (waveguide) and the front positions (free space) are presented. Second, the transmitted electric fields are presented for three cases: (a) scanning of a dielectric slit, (b) by varying the distance between the aperture and a dielectric sample, and (c) scanning of a dielectric groove. In the experiment, the lateral resolution with a two-slit and the depth resolution with grooves having various depths in rectangular format are described and the results show both resolutions to be much shorter than the wavelength. Finally, the scanned images of the letter N punched through a dielectric material and a leaf are demonstrated.

This paper presents the results of an investigation on the effect of a thin low-dielectric material (phantom shell) on measuring the Specific Absorption Rate (SAR) in the frequency range of 3 to 6 GHz. The International Electrotechnical Commission (IEC) has started to develop a SAR measurement procedure in order to cover such frequencies. In the procedure, the SAR is measured in a liquid phantom, which is a shell filled with tissue-equivalent liquid. Although the shell is thin and has low-dielectric properties, the influence of the phantom shell is thought to increase at higher frequencies. Therefore, an investigation using the transmission line model and the Finite-Difference Time-Domain (FD-TD) method was conducted. To verify the FD-TD results, measurements were also carried out. The calculation results using the FD-TD method agree well with the measurement results. If the frequency is higher, the SAR is affected by the shell even though the shell is thinner and has much lower dielectric properties than those of the tissue-equivalent liquid. Specifically, the SAR with the shell is approximately 1.3 times higher than without the shell at 5.2 GHz for the maximum case. The deviations in the loss and the thickness for the shell do not affect the SAR more than the relative permittivity.

The progress of LSI technologies makes it possible to fabricate 256 MDRAM. However, it depends on the cost effectiveness of device fabrication that LSI memory can continue to be the technology driver or not. It is indispensable to make the device, process, and equipment as simple as possible for next generation LSI. For example, wavefront technologies in lithography, high energy ion implantation, and simple DRAM cell with SOI structure or high dielectric constant capacitor, are under development to satisfy both device performance improvement and process simplicity.

An image type resonator method is proposed as a method to evaluate precisely the temperature dependence of dielectric material. At first, the temperature coefficients of the resonant frequencies, TCf are measured separately using the shielded dielectric resonators of three types; that is a parallel plate type, and an image type, and a MIC type resonator. Secondly, an intrinsic temperature coefficient of the resonant frequency TCf0, which is defined as the temperature coefficient of a resonant frequency when all the stored energy is confined inside a dielectric, is estimated from these measured TCf. Actually, the TCf0 values of a sapphire and (ZrSn) TiO4 rod are estimated from the TCf values measured for the resonators of three types. As a result, for the parallel plate type, the precision of TCf0 is about 0.1 ppm/. For the image and MIC types, the errors of about 0.5 ppm/ in the TCf0 values arise from the errors in the linear expansion coefficients of the resonators, rather than from the experimental errors in TCf. Then, another image type resonator is designed to estimate TCf0 within error of 0.1 ppm/. In this design, dimensions of the shielding cavity is determined to reduce the influence of the errors in the linear expansion coefficients on precision of the TCf0 estimation. Finally, for a (ZrSn) TiO4 ceramic rod, a TCf0 value estimated from TCf measured for the image type resonator is obtained with accuracy of about0.1 ppm/.