Communications: radio wave antennas – Antennas – High frequency type loops
Reexamination Certificate
1999-03-19
2001-06-05
Wong, Don (Department: 2821)
Communications: radio wave antennas
Antennas
High frequency type loops
C343S748000, C343S788000, C343S866000
Reexamination Certificate
active
06243045
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a loop antenna used for a data processing apparatus having a radio communication function for conducting radio transmission and reception between the data processing apparatus and a removable data storing medium having a radio communication function, and thereby conducting predetermined data processing such as data transmission and reception with the removable data storing medium. The present invention further relates to the removable data storing medium including this loop antenna.
In general, in a radio communication system for conducting communication using radio waves, it is necessary to use radio waves each having a strong electric field strength in order to conduct communication stably without being affected by its environment such as noise. Because of the stipulation of the radio law, however, it is impossible to radiate a radio wave having an unlimited strong electric field strength from a data processing apparatus. In the radio law, therefore, it is permitted to radiate a certain fixed strong radio wave for a specific frequency. However, the present frequency is strictly stipulated, and sufficient care is necessary for its use.
Assuming that the above described specific frequency has a wavelength &lgr;, &lgr;/2&pgr; is located near a measurement distance of 3 m stipulated by the radio law. When calculating the strength of a radiant electric field, it is typically difficult to make the theoretical calculation coincide with actually measured values when the distance is in the vicinity of &lgr;/2&pgr;. Furthermore, the environment of measurement also exerts a great influence. In other words, if an antenna is designed on a desk on the basis of various conditions and a measurement is actually conducted in the vicinity of 3 m, then a value largely different from the design value is obtained, and the radio law cannot be satisfied in many cases.
In other words, in a removable data storing medium having a loop antenna, it is desirable to send a signal with an electric strength as strong as possible. However, the electric strength is regulated by the radio law. Therefore, it is desirable to make an adjustment and ship the medium as a storing medium having the very highest electric field strength the regulation range will permit. If the electric field strength is calculated in a design stage and actual measured data is derived, then a portion other than the antenna portion functions as an antenna, and a very large difference occurs between the theoretical value and the actual value. In such a state that the electric field strength cannot be controlled accurately, therefore, there is a problem that it is impossible to design and ship the medium as a storing medium having the very highest electric field strength the radio law will permit.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a loop antenna for accurately implementing the electric field strength requested by the radio law by providing ground in parallel to the main body of the antenna to stabilize the electric field characteristic and making the design value of the antenna coincide with the actual measured value, and a removable data storing medium using this loop antenna.
In accordance with the present invention, an antenna device includes a loop antenna main body having a predetermined aperture area, and a conductor element insulated from the loop antenna main body, connected to a ground potential, and formed in parallel with the loop antenna main body.
In the above described configuration according to the present invention, the conductor element insulated from the loop main body is disposed in parallel with the loop main body which tends to become unstable in the electric field characteristic. As a result, the conductor element functions as the ground for the antenna main body. Since the electric field characteristic of the antenna main body can thus be stabilized, it becomes possible to bring the electric field strength in the design stage close to that in the actual measurement stage as compared with the conventional technique. In the design stage, therefore, it becomes possible to calculate the accurate electric field strength. It thus becomes possible to implement a loop antenna having a characteristic of a value which is infinitely close to the electric field strength requested by the radio law. As a result, the output of, for example, the removable data storing medium using this loop antenna has an electric field strength which is infinitely close to the electric field strength permitted by the radio law. As compared with the conventional technique, therefore, a higher value can be obtained.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
REFERENCES:
patent: 4373163 (1983-02-01), Vandebult
patent: 5327148 (1994-07-01), How et al.
patent: 5646633 (1997-07-01), Dahlberg
patent: 5838283 (1998-11-01), Nakano
patent: 5977921 (1999-11-01), Niccolai et al.
patent: 5982335 (1999-11-01), Faraone et al.
patent: 2724263 (1996-03-01), None
patent: WO 89/07347 (1989-08-01), None
Patent Abstracts of Japan, Shibata, Loop Antenna for Car-to-Ground Communication, vol. 006, No. 060 (E-102) Apr. 17, 1982 & JP 57 002102 A (Hitachi LTD), Jan. 7, 1982.
Kabushiki Kaisha Toshiba
Nguyen Hoang
Pillsbury & Winthrop LLP
Wong Don
LandOfFree
Removal data storing medium having loop antenna does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Removal data storing medium having loop antenna, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Removal data storing medium having loop antenna will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2538706