Patent Application
20230231320
This application claims the benefit of Taiwan Patent Application No. 111102009, filed on Jan. 18, 2022, which is hereby incorporated by reference for all purposes as if fully set forth herein.
The present invention relates to an array antenna, and particularly to a millimeter wave array patch antenna.
In order to reduce sidelobe gains of an array antenna, conventional millimeter wave antennas are arranged in series and/or in parallel. Sidelobes are lowered by changing the width ratios of the radiating elements or changing the power distribution ratios. However, such ratios require algorithm calibrations, so that the lowered sidelobes may be optimized, but it is difficult to fine-tune in different parts.
One objective of the present invention is to provide an array antenna, where the frequency bandwidth and center frequency may be adjusted by adjusting the length of the feeding section of microstrip feeding to the radiating element.
Another objective of the present invention is to provide an array antenna, where the length of the ground microstrip at the tail end of a radiating element may be adjusted and thereby effectively reducing sidelobe gains.
Yet another objective of the present invention is to provide an array antenna, where a serial antenna and a parallel antenna may be used simultaneously, and feeding sections of microstrip feeding to the radiating elements are in a horn shape and a groove shape. Desired frequency and bandwidth may be obtained by respectively adjusting lengths and widths of the feeding sections.
In order to achieve the foregoing objectives, the present invention provides an array antenna including a flexible substrate formed by a plurality of stacked liquid crystal polymer (LCP) layers with at least one feed point, and at least one serial antenna arranged on the flexible substrate. A microstrip is extended from the feed point and connects a plurality of radiating elements in series to form the serial antenna. The last one of the radiating elements in the serial antenna farthest from the feed point is connected to one end of the ground microstrip, and another end of the ground microstrip is short-circuited to the ground. The length of the ground microstrip is approximately one fourth of the wavelength of the center frequency of the array antenna.
Another aspect of the present invention provides an array antenna including a flexible substrate formed by a plurality of stacked LCP layers with at least one feed point. At least one power splitter is arranged on the flexible substrate and extended from the feed point, and splits into a plurality of branch feeders. At least one parallel antenna is arranged on the flexible substrate, where the parallel antenna has a plurality of parallel radiating elements respectively connected to the corresponding branch feeders by microstrips. Tail ends of the radiating elements are respectively connected to ends of ground microstrips, another ends of the ground microstrips are short-circuited to the ground, and a length of the ground microstrip is approximately one fourth of the wavelength of the center frequency of the array antenna.
Yet another aspect of the present invention provides an array antenna including a flexible substrate formed by a plurality of stacked LCP layers and having at least one feed point. At least one power splitter is arranged on the flexible substrate, extended from the feed point, and splits into a plurality of branch feeders. At least one parallel antenna is arranged on the flexible substrate, where the parallel antenna has a plurality of parallel radiating elements respectively connected to the corresponding branch feeders by microstrips. The microstrips are respectively extended to connect the plurality of radiating elements in series to form a plurality of serial antennas. A tail end of one of the radiating elements in the serial antennas farthest from the feed point is connected to one end of a ground microstrip, another end of the ground microstrip is short-circuited to the ground, and the length of the ground microstrip is approximately one fourth of the wavelength of the center frequency of the array antenna.
Further, a horn shaped feeding section is added to the microstrip feeding to each radiating element of the serial antenna. The width of the horn shaped feeding section is larger than a width of the microstrip, so that the array antenna may achieve a better frequency response by adjusting the matching condition of each radiating element.
Further, the microstrips of the parallel antenna present groove shaped feeding sections connecting to the radiating elements.
Further, lengths of the horn shaped feeding sections are adjustable, so that the array antenna may achieve a better frequency response by adjusting the matching condition of each radiating element.
Further, the distance between centers of two adjacent radiating elements is approximately equal to the wavelength of the center frequency of the array antenna.
Further, the length of each of the radiating elements in a direction of the microstrips is approximately half of the wavelength of the center frequency of the array antenna, and the optimal matching effect may be achieved.
Further, two sets of array antennas are substantially perpendicular to each other when used simultaneously.
Further, the microstrip forms a horn shaped feeding section in the microstrip feeding to each of the radiating elements, and the lengths of the feeding sections may be different.
The array antenna of the present invention has the following advantages: with a reduced number of patches, a horn shaped feeding section is added to each radiating element of the array antenna. The horn shaped feeding section may adjust the matching condition of each radiating element, so that the array antenna may achieve a better frequency response. In addition, a ground microstrip is connected at an end of the array antenna and is short-circuited to the ground. Through adjusting the distance between the radiating element at the end and the short-circuit ground, the matching of the array antenna and the center frequency of the optimal response may be achieved, and the sidelobe gains may be further reduced.
Embodiments of the present invention are described in detail below with reference to the accompanying drawings. The accompanying drawings are mainly simplified schematic diagrams, and only exemplify the basic structure of the present invention schematically. Therefore, only the components related to the present invention are shown in the drawings, and are not drawn according to the quantity, shape, and size of the components during actual implementation. During actual implementation, the type, quantity, and proportion of the components may be changed, and the layout of the components may be more complicated.
The following description of various embodiments is provided to exemplify the specific embodiments for implementation of the present invention with reference to accompanying drawings. The directional terms mentioned in present invention, like “above”, “below”, “front”, or “back”, refer to the directions in the accompanying drawings. Therefore, the used direction terms are intended to describe and understand the present invention, but are not intended to limit the present invention. In addition, in the specification, unless explicitly described as contrary, the word “include” is understood as referring to including the element, but does not exclude any other elements.
Referring to
The flexible substrate 1 is formed by a plurality of stacked liquid crystal polymer (LCP) layers and has at least one feed point 11. In this embodiment, the quantity of the LCP layers is at least three.
The serial antenna 2 is arranged on the flexible substrate 1, and microstrips 3 are extended from the feed point 11 to connect a plurality of radiating elements 4 in series to form the serial antenna 2. In this embodiment, the length of each of the radiating elements 4 in a direction of the microstrips 3 is approximately half (½λg) (±20%) of the wavelength of the center frequency of the array antenna, and the distance S between centers of two adjacent radiating elements 4 is approximately equal to the wavelength (λg) of the center frequency of the array antenna. The wavelength of the center frequency of the array antenna is 7.2 mm in this embodiment. In addition, each of the radiating elements 4 is a rectangular metal, or may be in other shapes such as square, circle, oval . . . etc., and not limited thereto.
A horn shaped feeding section 31 is arranged on each of the microstrips 3 in a feeding section of the each radiating element 4. Feeding sections 31 with the same or different widths are arranged where the microstrips 3 respectively connecting each radiating element 4. The width W of each feeding section 31 is greater than the width of the microstrip 3, and the length L of each feeding section 31 is adjustable. In this embodiment, an adjustment of the length L ranges from −0.3 mm to 0.5 mm and the lengths L may be all the same, partly the same, or all different. Negative values in the lengths L indicate that the lengths L are shortened, and positive values in the lengths L indicate that the lengths L are increased. Therefore, by adjusting the width W and/or the length L of the feeding section 31 of the each radiating element 4, the matching and center frequency of the array antenna may be adjusted.
Referring to
Referring to
Referring to
The flexible substrate 1′ is formed by stacked LCP layers and has at least one feed point 11′. In this embodiment, the quantity of the LCP layers is at least three.
The power splitter 6 is arranged on the flexible substrate 1′. The power splitter 6 extends from the feed point 11′ and splits into a plurality of branch feeders 3′. In this embodiment, the power splitter 6 is a microstrip four-way power splitter. The power splitter is common knowledge in related fields and the details will not be described here.
The parallel antenna 7 is arranged on the flexible substrate 1′. The parallel antenna 7 includes a plurality of parallel radiating elements 4′ respectively connected to branch feeders of the corresponding power splitter 6 by microstrips 3′. In this embodiment, the length of each of the radiating elements 4′ in a direction of the microstrips 3′ may be half (½λg) (±20%) of the wavelength of the center frequency of the array antenna, and the distance S′ between centers of two adjacent radiating elements 4′ is approximately equal to the wavelength (λg) of the center frequency of the array antenna. In this embodiment, the wavelength of the center frequency of the array antenna is 7.2 mm.
In addition, each of the radiating elements 4′ is a rectangular metal, or may be made of other materials and in other shapes such as square, circle, oval . . . etc. and not limited thereto. The feeding section 31′ formed in the feeding section of the each radiating element 4′ is in the shape of a groove.
Referring to
Referring to
The flexible substrate 1″ is formed by stacked LCP layers and has at least one feed point 11″. In this embodiment, the quantity of the plurality of LCP layers is at least three.
The power splitter 6′ is arranged on the flexible substrate 1″. The power splitter 6′ extends from the feed point 11″ and splits into a plurality of branch feeders.
The parallel antenna 7′ is arranged on the flexible substrate 1″. The parallel antenna 7′ includes a plurality of radiating elements 4″ respectively connected to branch feeders of the corresponding power splitter 6′ by microstrips 3″. The microstrips 3″ are respectively extended to connect the radiating elements 4″ in series to form a serial antenna 2′.
In this embodiment, the length of each of the radiating elements 4″ of the serial antenna 2′ is approximately half (½λg) (±20%) of the wavelength of the center frequency of the array antenna, and the distance S″ between centers of two adjacent radiating elements 4″ is approximately equal to the wavelength (λg) of the center frequency of the array antenna, and the wavelength of the center frequency of the array antenna may be 7.2 mm. In addition, each of the radiating elements 4″ is a rectangular metal, or may be in other shapes such as square, circle, oval . . . etc. and not limited thereto.
Moreover, the feeding section 31″ formed in the radiating element 4″ in the parallel antenna 7′ is in the shape of a groove. Another feeding section 31″ formed on the microstrips 3″ feeding each of the radiating elements 4″ by each of the first microstrips 3″ in the serial antenna 2′ is in a horn shape. The width W of the horn shaped feeding section 31″ is greater than the width of the microstrip 3″, and the length L′ of the horn shaped feeding section 31″ is adjustable. The adjusted lengths of the lengths L′ may be all the same, partly the same, or all different.
The tail end one of the radiating elements 4″ in the serial antenna 2′ farthest from the feed point 11″ is connected to one end of the ground microstrip 5″, and another end of the ground microstrip 5″ is short-circuited to the ground. The length of the ground microstrip 5″ is adjustable according to the wavelength of the center frequency of the array antenna. In this embodiment, the length of the ground microstrip 5″ is approximately one fourth (¼λg) (±20%) of the wavelength of the center frequency of the array antenna.
Referring to
In this embodiment, the other ends of the ground microstrip line are short-circuited to the ground, and the length of the ground microstrip is approximately equal to one fourth (¼λg) of the wavelength of the center frequency of the array antenna. Such embodiment according to the present invention can effectively reduce the sidelobes of the array antenna.
The above embodiments exemplify the principles, features, and effects of the present invention, but are not intended to limit the implementation scope of the present invention. A person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Any equivalent change or modification made using the contents disclosed by the present invention shall fall within the scope of the claims below.
| Number | Date | Country | Kind |
|---|---|---|---|
| 111102009 | Jan 2022 | TW | national |
