Patent Application
20210111494
The present invention relates to antennas.
Antennas are used in many areas , and as a not limiting example in wireless radio systems and other applications, in which they are required to be of a small size.
In applications requiring antennas of an omni-directional pattern, tuned monopole antennas as well as dipole antennas can be used as they exhibit good characteristics in terms of radiation pattern, input impedance, etc. The length of these antennas is determined by the desired operation frequency. The total length of a tuned dipole is a half wavelength at the center frequency and the length of a tuned monopole is a quarter wave of the center frequency. At low frequencies as well as in applications with space constraint, the length of such antennas can be inconveniently large. For this reason, various modified versions have been proposed in order to reduce the length of such antennas.
It is known to use non-straight line structures of different shapes for reducing the size (especially the length) of wire antennas. In these antennas, the radiating element is made in the shape of a non-straight line. Since the resonance frequency of these antennas is determined by the length of the current trace, the non-straight line structure allows for shortening the antenna length for a given (desired) trace length. However, while effective for reducing the antenna length, the non-straight line structure results in deterioration of the antenna performance in terms of radiation efficiency and gain.
Accordingly, it is an object of the present invention to provide an antenna which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated in an antenna which has at least one radiating element having a straight part with one end extending from a feed point and with an opposite end, and a non-straight part extending from the opposite end of the straight part.
When the antenna is designed in accordance with the present invention the efficiency and gain of the antenna is not significantly affected by the non-straight part of the radiating element, and therefore it substantially eliminates the problems caused by the limitations and disadvantages of antennas with radiating elements composed exclusively of non-straight parts.
According to a further feature of the present invention the non-straight part of the at least one radiating element is formed as a meandering non-straight part.
According to a further feature of the present invention the non-straight part of the at least one radiating element is formed as a wavy non-straight part.
According to a further feature of the present invention the antenna is a dipole antenna and has two radiating elements located at opposite sides of the feed and each including the straight part having the one end extending the feed and the opposite end, and the non-straight part extending from an opposite end of the straight part.
According to a further feature of the present invention the antenna is a monopole antenna and has at least one radiating element with the straight part having one end extending the feed and the opposite end and the non-straight part extending from an opposite end of the straight part, with the one radiating element located at one side of the feed, and a ground portion constituting a voltage nullifier circuit is located connected to another opposite feed, directly or through a conducting pad.
According to still a further feature of the present invention the nullifier includes a non-straight portion extending from the opposite side of the area of the feed and an additional straight portion extending under this portion toward the feed and connected with the upper non-straight portion at an end which is opposite to the area of the feed.
According to still a further feature of the present invention the non-straight part of the at least one radiating element has an upper non-straight portion extending from the opposite end of the straight part and a lower non-straight portion extending toward the area of the feed substantially along the upper non-straight portion and connected with the upper non-straight portion at an end with each distant from the area of the feed.
According to a further feature of the present invention in the radiating element the non-straight part extending from the opposite end of the straight part is oriented transversely to the straight part.
An antenna 1 according to one embodiment of the present invention is shown in
The contribution of the non-straight portions 4 to the antenna radiation efficiency is low due to the fact that anti-phase currents flow in parallel segments. To obviate this disadvantage, the antenna uses the non-straight portions 5 which constitute only as a part of each radiating element 2 and each extend from the end of the corresponding straight portion 3, which end of the straight portion is opposite to the feed area.
The non-straight portions are located away from the feed, so that the current flowing in this part is of a low amplitude. Therefore, the dipole arms near the feed are straight-lines as in the case of conventional dipoles, and as such their contribution to the radiation is dominant, as in the case of conventional tuned dipoles.
While the resonance frequency of the antenna is determined by the length of the whole current path in the antenna including the straight portions 3 and the non-straight portions 5, the main contribution to the radiation stems from the straight portions 3, in which the current amplitude is high. The ratio between the lengths of the straight portions 3 and the non-straight portions 5 can be designed as an optimum compromise for a minimal antenna length and a maximum efficiency and gain.
The antenna 1a according to a further feature of the present invention having a monopole configuration is shown in
The nullifier 6 consists of a rectangular loop in which an upper non-straight portion 7 extends from the opposite side of the area of the feed and formed for example as a meandering portion or a wave-shaped portion and an additional lower straight portion 8 extending under the upper non-straight portion 7 toward the area of the feed. The lower straight portion 8 is connected with the upper non-straight portion 7 at an end which is opposite to the area of the feed. The nullifier 6 operates as a grounding and nullifies a potential at one of the feed points.
The antenna 1b according to a further embodiment of the present invention is shown in
The antenna 1c according to a further embodiment of the present invention is shown in
In the antenna of the present invention the radiating elements can be three-dimensional and the antenna can have a three-dimensional monopole configuration as shown in
The antenna of the present invention can also have a cross-shaped dipole configuration as shown in
The antenna of the present invention can also be printed on a dielectric substrate 21 as shown in
In the antenna of the present invention a high-permittivity substrate on which the radiating elements are arranged can be used for further reduction of the antenna dimensions.
The antenna of the present invention can be realized in wired antenna configuration, such as monopole o r dipole, in different ways. These include:
The antenna of the present invention can also comprise additional components selected from the group consisting of reactive components, active components, and both and obtaining or improving matching between the antenna and a source or a load.
What is desired to be protected by Letters Patent is set forth in particular in the appended claims.
| Number | Date | Country | |
|---|---|---|---|
| 62915054 | Oct 2019 | US |
