Among the computer programs for the analysis of wire antennas, designed to run on personal computers, AWAS produced by A.R.Djordjevic et al. and WIPL by B.M.Kolundzija et al. are compared. In both programs, the electric field integral equation (EFIE) is solved with the current expansion functions of polynomials. The feed point currents on the hollow cylindrical dipole antenna with length of 0.4 to 1.0 wavelength and with radius of 0.0002 to 0.01 wavelength are compared with the reference data solved by EFIE with the current expansion functions satisfying the edge condition at the antenna end.
An active loop antenna for television receiver is presented and its broadband operation is reported. A loop antenna and a coplanar waveguide (CPW) is printed on a thin dielectric film. The CPW is located perpendicularly to the plane of loop. The GaAs FET FHC30LG is integrated between the feed point of loop and the CPW. A chip inductor is connected between loop antenna and CPW. Actual gains more than 8dBd (relative values to the halfwave dipole antenna) are obtained at the frequencies for television channels 1-3 from 90 to 108MHz and channels 13-62 from 470-770MHz in Japan.
The repeater antenna in receiving the electromagnetic signal from the base station of the portable radio service and relaying to the portable radio unit within the automobile is analyzed numerically and experimentally. This antenna is fabricated on the thin film and stuck on the window glass of the automobile. The current distribution, the imput impedance, and the radiation characterisitics as the transmitting antenna are calculated by using the computer program AWAS produced by A.R.Djordjevic et al., and discussed the influence of glass plate on the input impedance characteristics.
We have developed a new type of the transmission line type antenna called a modified transmission line antenna (MTLA). In order to achieve low profile structure for this antenna, we tried to used a knowledge of folded antenna. In this paper, we at first explain the fundamental characteristics of the MTLA, and then introduce folded type modified transmission line antenna (FMTLA) for an application of the MTLA to the mobile communication.
FDTD (Finite-Difference Time-Domian) Method is one of useful method to analyze maicrostrip antennas. In this paper, a stacked maicrostrip antenna is analyzed using FDTD Method, and Electrc and magnetic fields of the antenna are discussed.
For the base station antenna of cellular mobile telephone systems, a beam tilting antenna, which achieves down tilt in the horizontal plane to control the zone shape, is desired. In this paper, for the beam tilting of the antenna with an impedance load, we present and study the method for determining the load value to realize the required tilt angle.
In this paper, we investigate experimentally an efficiency and a gain of microstrip array antennas composed of stacked patches. The parasitic element stacked above and near the fed element widen the bandwidth. The other parasitic e1ements stacked at intervals of about 0.5 wave length above the fed element increases the gain. A microstrip antenna has both of high gain and wide band by stacking these parasitic elements. We design the microstrip planar array antenna (2×2 elements) which is composed of the stacked patches as an element of array, and discuss characteristics of the efficiency and the gain versus element spacing.
We have studied the simplified DGPS using two GPS receivers which are placed at positioning and reference point. In this paper, we investigate the effect of the distance between positioning and reference point on the positioning error, and also the relation between mask angle and positioning error. We cofirm experimentally that positioning error is about 5m of positioning accuracy at the distance from 20m to 40km, and the variation of mask angle has little effect on the positioning accuracy of the simplified DGPS in comparison with the usual GPS positioning.
We, NTV VTR Operating Division, had renovated our editing system. With this renovation, our editing system is now fully digitalized. Now we are able to edit in 525 line progressive scanning signal (525p) and "Wide-Clearvision" (EDTV-II), in addition to present NTSC signal.
On 13th july '95 NTV has aucceeded to be the the first in Japan officially broadcasting of EDTV-II programs. After that, NTV has been btroadcasted a lot of EDTV-II programs. Basically, EDTV-II has compatibility with NTSC. But, for EDTV-II brcadcasting. We need sum new equipments and defferent operations from NTSC broadcasting. We report the broadcasting system and operation for EDTV-II and NTSC program in NTV master control room.
We have made a signal converter which converts interlaced telecine video to progressive video signal on an experimental basis. There were reports of same kind of telecine video converters using a method of detecting pull-down sequence from input video. But, this method has a problem that detection of pull-down sequence may mistaken when sequence of same images are input. This paper reports about a new method for the interlaced telecine video converter which uses timecode to lock to pull-down sequence.
We have deve1oped a new Ku-band portable digital SNG (Satellite News Gathering) RF terminal that uses a low sidelobe flat antenna. The antenna consists of 16 planar microstrip subarray antennas, and each of these has a phase shifter and a solid-state power amplifier with output power of 5 W and efficiency of 21%. We have used this system successfully in various experiments on transmission via a satellite. After about 20 rounds of experiments, we confirmed the stable transmission of a QPSK signal from the SNG RF terminal and that the terminal was capable of electronic satellite tracking within ±3 degress.
In order to overcome rain attenuation on down-links in the satellite broadcasting, a system is proposed in this paper to provide additional power to the worst 3 beams of a 10-beam antenna on board a satellite. Simulation is carried out by converting the AMeDAS rain data to the attenuation at 21 GHz. Analyses are made on its performance depending upon conditions, such as, how to determine 3 beams to be worst, which factor to be used for that selection, and intervals of the power control. Selecting the worst 3 beams every 1 hour by using amount of locations exceeded by a specified level of attenuation within each beam in before one hour, % time of outage in a year is expected to be reduced to 0.4,approximately.
In this paper, the monopole antenna loaded by a short-circuited coaxial stub is analyzed. The moment method has been used to calculate the input impedance, resonant frequency and band width. Practical design parameters to optimize the antenna size and the band width of the loaded monopole antenna are presented.
The Differential GPS is well known as the effective system for positioning acquisition. We bave studied about a simplified Differential GPS using two GPS receivers. In this paper, we discuss the method for improving the positioning accuracy by the after processing of positioning data. It is cleared that about 50cm positioning accuracy is obtained by after processing of crosscorrelation of dispersion data pattern. Presented is not a real-time positioning, but available for high accurate positioning with GPS receiver which are on the market and easy to obtain.
A New analysis method of a transformer for a high frequency band is presented. In a high frequency band, the primary coil and secondary coil of the transformer are a transmission line and this transmission line is a distoributed LC line. We introduced the equivalent circuit of this transforner from the concept of the distributed LC line.
We have developed an automatic painting equipment, which paints a cylindrical M.F antenna tower with guy wire as moves up and down. By using this equipment, we can get high efficiency and more short time for painting work. In this system, the moving carrier with spray guns moves up and down along the antenna controlled by the winch placed on the ground. The method of painting is airless spray method with chlorinated rubber paint. It can paint antennas which are 500〜1200mm in diameter and 100〜240m in hight. It can paint whole circumference by using open and shut arm at once. The painted thickness is above 30μm. We have painted the antenna of NHK Kasuga transmitting station in Fukuoka prefecture for the first time.
In 1992,the ITU Conference WARC 92 allocated the frequency of 2.6 GHz to digital audio broadcasting. When the satellite signals pass through the ionosphere, the reception signal is influenced by ionospheric irregularities on sporadic E layer. The occurrence of this phenomenon is closely related to the sporadic E layer in the ionosphere, the value of the sporadic E layer electron density is large in the East Japan. We gave it our general consideration based on the results by analysis of ionoshperic data in Japan.