Yasuhiro Kazama

Novel phased array antenna with elements of conical beam patterns

In this paper, we propose a phased array antenna with elements having the conical radiation pattern. It has been shown that beam scanning gain characteristics are attractive as compared with a conventional phased array antenna with elements having a vertical radiation pattern. We also propose to apply a partial drive technique to the above mentioned phased array antenna. It has been shown that the proposed partial drive array can reduce the number of the driven elements to 42% by the penalty of 1.5 dB, and is attractive for commercial applications.

Polarization tracking phased array antenna with cross dipole antenna

In this paper, a phased array antenna (PAA) using crossed dipole antenna elements is examined. A partially driven array technique is used for the array antenna. From the analyzed results, it is shown that the element antenna has conical radiation pattern. Using the element antenna, the beam scanning characteristics of the PAA is investigated. It is found that this array antenna can scan the beam in all directions successfully. Therefore, this PAA can be applicable to the mobile station antenna of satellite communications.

Polarization tracking phased array antenna with cross dipole antenna -measured results-

Recently, a phased array antenna (PAA) for commercial mobile satellite communications receives great attention [1], [2]. The communications satellite on a geostationary orbit is visible at elevation angle from 30deg. to 60deg. in Japan. Therefore, it is desirable that a main lobe of the element antenna is in the satellite direction. For this reason, a PAA composed of dipole antenna with conical radiation pattern has proposed [3]. The dipole antenna radiates linearly polarized wave. Therefore, in the case that the PAA is installed on a car roof for such satellite communications, the antenna cant track the satellite when the car curves at the corner of the street. Then, the communications is down at that time. For this reason, we also have proposed a PAA consisting of a crossed dipole antenna of which the radiation pattern is conical with low radiation intensity in the zenith direction, and show the simulated results [4].

A phased array antenna using cross dipole antenna for mobile satellite communications

In this paper, we propose a phased array antenna which consists of crossed dipole antenna with a reflector as an element antenna. The element antenna is designed by optimizing its parameters. The main and cross polarization characteristics of the right and left side beam scanning of the fabricated 19-element array antenna is measured. Next, the experimental results of the beam scanning characteristics is discussed. It is shown that the measured results is effective to a satellite communications mobile station.

A study on phased array antenna using MSA composed by 3-patches

In this paper, a new type of phased array antenna using bi-layered microstrip antenna (MSA) composed by 3-patch element is proposed. An element antenna of the array has conical radiation pattern at E- and H-plane. Firstly, the bi-layered MSA of conical radiation pattern is examined analytically by an electromagnetic field simulator. It is shown that desirable radiation patterns are obtained. Then, using the element antenna, the beam scanning characteristics of a 4 × 4-element array antenna is investigated. As a result, the proposed antenna is promising in use of mobile satellite communications.

A study on dipole antenna having conical radiation pattern with EBG as a reflector

In this study, to achieve low profile dipole antenna having conical radiation pattern for satellite communications, we investigate the dipole antenna with EBG as a reflector. Firstly, the EBG structure is designed and simulated at 12.5 GHz. Next, radiation patterns of the dipole antenna arranged above the PEC and EBG are investigated and compared. Finally, mutual coupling effect of 2-element array antenna, which is with the PEC or EBG as a reflector is examined.

Beam scanning characteristics of bi-layered patch antenna with slots having conical radiation pattern

A new type of bi-layered microstrip antenna (MSA) with conical radiation pattern for mobile satellite communication is proposed as an element antenna in this paper. The MSA consists of three patches with slots on bi-layered substrate and the feed is passing through the ground of the substrate. Thus the element antenna is first coarsely designed and the performance is optimized by electromagnetic simulator at 14.25 GHz. The optimized element antenna has the conical radiation pattern in two orthogonal planes. Using the element antenna, the beam scanning characteristics of 16-element linear array antenna are investigated. The simulated results show that the proposed bi-layered MSA would be suitable for the mobile satellite communications.

A large number of phased array antenna with low grating lobes using partially driven technique

In this paper, a phased array antenna which has a large number of element antenna and low grating lobes is described. The element antenna has a conical shaped radiation pattern which is suitable for a mobile satellite communications. To reduce a number of phase shifter, partially driven array technique which is one kind of thinned array is employed. The beam scanning characteristics of 243-element array antenna are investigated computationally.

Beam secanning characteristics on 16-element array antenna using double-loop antenna

In this paper, a phased array antenna for a linearly polarized wave is proposed for mobile satellite communications antennas. An element antenna consists of two loop antennas concentrically located on a dielectric substrate with a reflector and these loop antennas work at dominant and second mode resonant frequencies. Firstly, characteristics of each loop antenna fed by a microstrip transmission line (MSL) are simulated and measured to investigate fundamental radiation characteristics of these antennas. Next, a 16-element linear array antenna is simulated and measured. It is shown that the proposed antenna is suitable for the mobile satellite communications antenna.

A study on double-loop array antenna for mobile satellite communications

A double-loop antenna is proposed for mobile satellite communications antennas having linear polarized wave. The antenna consists of two loop antennas concentrically located on a dielectric substrate with a reflector and these antennas act as dominant and second mode resonant frequencies. Firstly, characteristics of each loop antenna are calculated to investigate fundamental radiation characteristics of these antennas by using an electromagnetic simulator. Next, beam scanning characteristics of the double-loop array antenna are investigated. Then, a feeding method for the proposed antenna is examined by using a microstrip transmission line (MSL). Finally, based on the calculated result, an antenna element is fabricated and tested. It is confirmed that the proposed antenna would be suitable for the beam scanning antennas.