Patent Application
20240047896
This invention relates to antennas for wireless communication; and more particularly, to an antenna fabricated on a flexible polymer substrate, the antenna including: a radiating element and a ground conductor forming a plurality of ground resonators for providing high performance over a wide bandwidth.
There is a continued need for improved antennas, especially flexible antennas, having a flexible configuration for placing on curved surfaces of various products, and being capable of tuning to wide bands (for example: 700 MHz-2700 MHz range).
A need exists for an antenna capable of multiple resonance frequencies at a wide band, for example between 700 MHz and 2700 MHz, especially such an antenna that is capable of forming about a curved surface of a device.
After much testing and experimentation, the antenna architecture as disclosed herein has been discovered, which provides efficient signaling at multiple resonance frequencies over a very wide band between 700 MHz and 2700 MHz. The performance of the disclosed antenna exceeds that of conventional antennas and is further adapted on a flexible substrate and configured to conform about a curved device surface for integrating with a plurality of host devices.
Advantageous Effects of Invention
In addition to the wide band performance, the flexible polymer substrate provides the capability to conform the antenna about a curved surface of a device. While curved, the antenna continues to exhibit efficient performance over a wide band.
In various embodiments, an antenna is disclosed which includes: a substrate, an antenna radiating element disposed on the substrate, and a ground conductor, wherein the ground conductor comprises: a ground patch, a first ground resonator, a second ground resonator, and a third ground resonator; wherein the ground conductor surrounds the antenna radiating element about two sides thereof and provides for multiple resonant frequencies forming a wide band response.
The antenna radiating element of the antenna assembly (that which is fed by the center element of the coaxial cable) is known to work well in other designs provided that the ground plane is sufficiently large. A motivation of the instant antenna design is to improve the ground conductor of the antenna assembly to work with a flexible substrate and to achieve sufficient efficiency in the smallest form possible. In addition, the ground conductor is configured to allow the cable shield and its end connection to act as an extension to the ground plane.
Modern cellular applications, including 3G and 4G, often require the combination of high efficiency and small size over a large set of bands in the 700-2700 MHz range. The cable-fed flexible polymer antenna assembly is a commonly-used implementation of antennas for this market. It is often challenging to integrate such antennas into compact devices without degradation of return loss (and thus efficiency) due to proximity of nearby metal objects or improper routing of the cable.
This disclosure presents a novel antenna architecture with acceptable efficiency in a very small form using a known antenna radiating element and a unique multi-section wrapping ground conductor that is virtually extended by the feed cable. The structure was designed to concentrate the efficiency in those frequency bands where is it needed at the expense of those frequencies where the efficiency is not needed.
It is difficult to design an antenna with a small size that operates efficiently over all cellular bands in modern use.
On typical cable-fed quasi-dipoles, the ground is often too small for stable operation and the cable shield is relied upon to provide a ground conductor. This sort of cable-ground is non-ideal, as it cannot implement a resonant element.
For a small size antenna, in order to produce high efficiencies at low frequencies in the wide range of 700 MHz-960 MHz, it was discovered that the use of multiple wrapping ground resonators, each being progressively larger toward the outside, works well. Moreover, with the multiple ground resonators, the cable shield can act as the last resonator structure for the lowest frequency required.
It is known by experiment that covering the antenna radiating element with copper tape will produce low band performance that is not as good but still marginal and poor high band performance. It is also known that by covering the ground conductor with copper tape, the low band performance is nonexistent and high band performance is not as good but marginal. Therefore, it is necessary to have the proposed patterning on the ground conductor, not just a conductive sheet the same size.
A simple dipole would require approximately 210 mm of length to perform at 700 MHz.
With the disclosed antenna architecture, we measure high efficiencies down to 650 MHz within a space of 58 mm.times.67 mm. Thus, we can achieve better efficiencies at a much smaller size.
In addition, by forming the antenna assembly on a flexible substrate, we can conform the shape of the antenna assembly to any surface, such that the antenna can be mounted, or we can bend the antenna one time or multiple times.
The antenna has two main subsections: the antenna radiating element and the ground conductor. The ground conductor is novel in that it is composed of multiple subelements, each progressively larger and farther from the antenna radiating element, so that the last element is effectively the cable shield and its connection, i.e. typically a PCB ground. This gives a known and proper way to route the cable.
In one aspect, the antenna is combining the antenna radiating element with a new type of ground conductor composed of multiple (here three) sub-elements which wrap around and progressively get larger as the sub elements (resonators) approach the outer periphery of the antenna assembly. The cable shield will act as final element due to routing.
In another aspect, we propose using mini-coax cable as feeding technique of the antenna.
In yet another aspect, we propose manufacturing the antenna structure on flexible substrate, such as a polyimide (Kapton®) substrate, having the convenience of attached the antenna to any curved surface, or bend the antenna multiple times.
Now turning to the drawings which illustrate an example,
As appreciated from
Moving downward along a first edge of the antenna assembly as shown, a first ground resonator 210 extends horizontally from the edge along a first body portion 211 and is bent at a right angle toward a first terminal portion 212.
A second ground resonator 220 extends from the first edge of the antenna assembly as shown, the second ground resonator including a second horizontal body portion 221, a second vertical body portion 222, and a second terminal portion 223. The second ground resonator includes a length greater than that of the first ground resonator. The second ground resonator is also positioned along the ground conductor at a distance that is greater than that of the first ground resonator. The second vertical body portion 222 of the second ground resonator 220 is aligned parallel with the first terminal portion 212 of the first ground resonator, with a first gap extending therebetween.
A third ground resonator 230 extends from the ground conductor 200 forming a third horizontal body portion 231 which is oriented parallel with respect to the second horizontal body portion 221 of the second ground conductor, and a third vertical body portion 232 extending perpendicularly from the third horizontal body portion 231. The third ground resonator includes a length that is larger than each of the first and second ground resonators, respectively. Moreover, the third ground conductor is positioned at a distance from the radiating element 100 that is larger than that of the first and second ground resonators, respectively. A second gap is formed between the second ground resonator and the third ground resonator. The ground conductor 200 further includes cleave portion 241 extending between the first edge and the third ground resonator at an angle less than ninety degrees.
Referring back to
As used herein, each of the terms “horizontal”, “vertical”, “parallel” and/or “perpendicular”, or variations of these terms such as “horizontally”, etc., are used with reference to the specific orientation as shown in the corresponding illustrations.
The instant antenna assembly as disclosed herein provides useful efficiency and performance in the wide band between 700 MHz and 2700 MHz, which can be used in cellular communications among other communication networks.
100 antenna radiating element
200 ground conductor
201 ground patch
210 first ground resonator (sub-element)
211 first body portion
212 first terminal portion
220 second ground resonator (sub-element)
221 second horizontal body portion
222 second vertical body portion
223 second terminal portion
230 third ground resonator (sub-element)
231 third horizontal body portion
232 third vertical body portion
241 cleave portion
401 ground element
402 feed
500 coaxial cable
501 connector
550 substrate
601 liner
602 adhesive layer
603 solder mask layer
604 flexible polymer substrate
605 copper layer
606
a;
606
b solder mask
607
a;
607
b conductive pads
This application is a continuation of, and claims the benefit of priority to, co-owned and co-pending U.S. patent application Ser. No. 17/717,473 filed on Apr. 11, 2022 of the same title, which is a continuation of, and claims the benefit of priority to U.S. patent application Ser. No. 17/140,666 filed on Jan. 4, 2021 of the same title, now U.S. Pat. No. 11,329,397 issued on May 10, 2022, which is a continuation of, and claims the benefit of priority to co-owned U.S. patent application Ser. No. 16/665,942 filed on Oct. 28, 2019 of the same title, now U.S. Pat. No. 10,886,633 issued on Jan. 5, 2021, which is a continuation of, and claims the benefit of priority to, co-owned U.S. patent application Ser. No. 16/140,977, filed Sep. 25, 2018 of the same title, now U.S. Pat. No. 10,461,439 issued on Oct. 29, 2019, which is a continuation of, and claims the benefit of priority to, co-owned U.S. patent application Ser. No. 15/351,263, filed Nov. 14, 2016 of the same title, now U.S. Pat. No. 10,103,451 issued on Oct. 16, 2018, which claims the benefit of priority to co-owned U.S. Provisional Application Ser. No. 62/254,140 filed Nov. 11, 2015 of the same title, the contents of each of the foregoing being incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62254140 | Nov 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17717473 | Apr 2022 | US |
| Child | 18217731 | US | |
| Parent | 17140666 | Jan 2021 | US |
| Child | 17717473 | US | |
| Parent | 16665942 | Oct 2019 | US |
| Child | 17140666 | US | |
| Parent | 16140977 | Sep 2018 | US |
| Child | 16665942 | US | |
| Parent | 15351263 | Nov 2016 | US |
| Child | 16140977 | US |
