Technical Field

[0001] The present invention generally relates to an ultra-wideband monopole antenna for an indoor 5G fixed wireless, small cell or indoor coverage application.

Background Art

[0002] For indoor 5G fixed wireless, small cell and indoor coverage system, there is a need to have a multi band monopole antenna with an extremely low and slim profile.

[0003] For an ultra-wideband monopole antenna to cover the full 5G band, 600-6000MHz, the challenge that arises is that the required operating frequency bandwidth is very wide compared with that of a conventional monopole antenna used in telecommunication system. Therefore it is very challenging to design a monopole antenna in an extremely low and slim profile to deliver flat and linear gain figure and a high radiation efficiency in the whole operating frequency bandwidth.

Summary Of The Invention

[0004] The present invention preferably provides an antenna assembly for an ultra-wideband monopole antenna with two quarter wavelength conductors that are uniquely arranged electrically and physically in an extremely low and slim profile.

[0005] The present invention is an ultra-wideband monopole antenna for an indoor 5G fixed wireless, small cell or indoor coverage application where both attractive form factor and aesthetical appearance are required.

[0006] In particular, an ultra-wideband antenna is designed for a flat and linear gain figure and an high radiation efficiency with an extremely low and slim profile. [0007] The achievement of an ultra wideband monopole antenna described herein is through the unique arrangement of two quarter wavelength conductors.

[0008] One aspect of the present invention is an ultra-wideband monopole antenna assembly having an extremely low and slim profile. The antenna assembly comprises a first quarter wavelength conductor comprising a first flat portion, and a second quarter wavelength conductor comprising a second flat portion. Each of the first quarter wavelength conductor and the second quarter wavelength conductor is configured to transmit and/or receive an electromagnetic signal. The antenna assembly operates on a 5G band. The flat portion of the first quarter wavelength conductor and the flat portion of the second quarter wavelength conductor are arranged and located perpendicular and intersect each other.

[0009] Another aspect of the present invention is an ultra-wideband monopole antenna comprising a base, a first quarter wavelength conductor comprising a first flat portion and two identical curved wings, and a second quarter wavelength conductor comprising a second flat portion and two identical curved wings. The first quarter wavelength conductor and the second quarter wavelength conductor preferably delivers 600-960MHz and 1710-6000MHz operating frequency bandwidth.

[00010] The antenna assembly is preferably a ground plane dependent antenna. The two identical curved wings of the first quarter wavelength conductor and two identical curved wings of the second quarter wavelength conductor are preferably arranged and located concentrically and have a same center. A predetermined height of the first quarter wavelength conductor, together with two identical curved wings, preferably deliver a first operating frequency bandwidth with restricted height. The pre-determined radius of the two identical curved wings of the first quarter wavelength conductor, together with the two identical curved wings of the second quarter wavelength conductor, preferably deliver a first and a second operating frequency bandwidth as required with restricted diameter. A pre-determined height of the flat portion from both the first and second quarter wavelength conductors plus the lengths of two identical curved wings from the first and second quarter wavelength conductor, preferably contribute to a flat and linear gain figure across an ultra- wideband 5G frequency band. A shape and location of the identical curved wings from the first and second quarter wavelength conductors, preferably contribute to a high radiation efficiency with extremely low and slim profile.

[00011] A flat portion of the first and second quarter wavelength conductors is preferably made from FR4 PCB and the identical curved wings are preferably made from stainless steel.

[00012] The antenna assembly preferably further comprises a coaxial connector with a center conductor connected onto the joined flat portions from both the first and second wavelength conductors.

[00013] A shape and dimension of the identical curved wings from both the first and second quarter wavelength conductors are alternatively not identical. The curved wings are preferably not limited to having the same radius or distance from the center. The curved wings are preferably not limited to curving shape as long as this monopole antenna is within the restricted radius. The two identical curved wings from the first quarter wavelength conductor are preferably not limited to having the same height when connected onto the flat portion of the first quarter wavelength conductor as long as the monopole antenna is within the restricted height. The two identical curved wings from the second quarter wavelength conductor are preferably not limited to having the same height when connected onto the flat portion of the second quarter wavelength conductor.

Brief Description Of The Drawings

[00014] FIG. l is a perspective view of an ultra wideband monopole antenna.

[00015] FIG. 2 is a top plan view of an ultra wideband monopole antenna. [00016] FIG. 3 is a graph illustrating a return loss of the ultra wideband monopole antenna.

[00017] FIG. 4 is a perspective view of the details of the flat and curved portions from the first and second quarter wavelength conductors of the ultra wideband monopole antenna.

[00018] FIG. 5 is a graph illustrating a peak gain of the ultra wideband monopole antenna across the whole operating frequency band.

[00019] FIG. 6 is a perspective view of identical curved wings from the first and second quarter wavelength conductors of the ultra wideband monopole antenna.

[00020] FIG. 7 is a graph illustrating a radiation efficiency of the ultra wideband monopole antenna.

[00021] FIG. 8 is a perspective view of the physical structure of the first and second quarter wavelength conductors of the ultra wideband monopole antenna.

Best Mode(s) For Carrying Out The Invention

[00022] As shown in FIG. 1, an ultra wideband monopole antenna 10 comprises a first quarter wavelength conductor 1 configured for a first operating frequency and a second quarter wavelength conductor 2 configured for a second operating frequency.

[00023] In a preferred embodiment having a unique arrangement of two quarter wavelength conductors 1 and 2 as shown in FIG. 1, each quarter wavelength conductor 1 and 2 comprises a flat portion la and 2a edged with two identical curved wings lb, lc, 2b and 2c. The flat portion la of the first quarter wavelength conductor 1 and the flat portion 2a of the second quarter wavelength conductor 2 are preferably arranged and located perpendicular and intersecting to each other. [00024] In a two curved wings embodiment, there are two identical wings, with an equal radius or distance to the center, which are connected on two edges of the flat portion of each quarter wavelength conductor, thereby widening the matching bandwidth of the first and second operating frequency to provide a bandwidth of 617-960MHz and 1710-6000MHz.

[00025] In a flat and curved portion from the quarter wavelength conductor embodiment of an ultra wideband monopole antenna 10, the two identical curved wings lb and lc of the first quarter wavelength conductor 1 and the two identical curved wings 2b and 2c of the second quarter wavelength conductor 2 are preferably arranged and located concentrically and have a same center.

[00026] In a restricted height embodiment, a pre-determined height of the first quarter wavelength conductor, together with two identical curved wings, deliver a first operating frequency bandwidth as required for a 5G application. The pre-determined height preferably ranges from 70 to 90 millimeters (“mm”), and is most preferably 78mm, which provides 617-960MHz of the 5G operating band.

[00027] In a restricted radius embodiment, a pre-determined radius of two identical curved wings of the first quarter wavelength conductor, together with two identical curved wings of the second quarter wavelength conductor, deliver a first and second operating frequency bandwidth as required for a 5G application. The pre-determined radius of two identical curved wings of the first quarter wavelength conductor preferably ranges from 10mm to 15mm and is most preferably 13.5mm, which contributes to the lower band, 617- 960MHz, and the pre-determined radius of the two identical curved wings of the second quarter wavelength conductor preferably ranges from 10mm to 15mm and is most preferably 12.3mm, which contributes to the upper band, 1710-6000MHZ. [00028] In an ultra wideband matching bandwidth embodiment, the first and second quarter wavelength conductors 1 and 2 are joined to deliver ultra wideband frequency in the 5G frequency bands.

[00029] In a flat and linear gain embodiment, a pre-determined height of a flat portion la and 2a from both first and second quarter wavelength conductors 1 and 2, plus the lengths of two identical curved wings lb, lc, 2b and 2c from the first and second quarter wavelength conductors 1 and 2, contribute to the flat and linear gain across the ultra-wideband frequency band. The pre determined length of the two identical curved wings lb and lc from the first quarter wavelength conductor 1 preferably ranges from 12mm to 20mm, and is most preferably 16.5mm, which contributes 3 to 4dBi flat and linear gain at the lower band, 617-960MHz, of 5G operating band.

[00030] In a high radiation efficiency embodiment, a shape and location of the two identical curved wings lb, lc, 2b and 2c from the first and second quarter wavelength conductors 1 and 2 contribute to a high radiation efficiency with the extremely low and slim profile of the ultra wideband monopole antenna 10. Each quarter wavelength conductor 1 and 2 comprises a flat portion la and lb edged with two identical curved wings lb and lc, 2b and 2c. The flat portion la of the first quarter wavelength conductor 1 and the flat portion 2a of the second quarter wavelength conductor 2 are preferably arranged and located perpendicular and intersecting to each other. The two identical wings lb and lc, 2b and 2c are connected onto two edges of the flat portion la and 2a of each quarter wavelength conductor 1 and 2, widening the matching bandwidth of the first and second operating frequency. Preferably, the identical curved wings lb and lc of the first quarter wavelength conductor 1 and identical curved wings 2b and 2c of the second quarter wavelength conductor 2 are preferably arranged and located concentrically and having the same center. With such arrangement as described above, this invention not only provides a low and slim profile, but also provides more than 80% average radiation efficiency. [00031] In a cost effective design, the antenna 10 has a flat portion la and lb from the first and second quarter wavelength conductors 1 and 2 made from FR4 PCB and the curved wings lb, lc, 2b and 2c composed of a stainless steel. This cost effective design makes the ultra wideband monopole antenna 10 very cost effective, competitive and easy to be built.

[00032] In other version, the ultra wideband monopole antenna 10 uses materials such as aluminum, brass, metal alloy, ceramic, FPC, LDS (Laser Direct Structuring) and PDS (Printing Direct Structuring).

[00033] A frequency embodiment is a multiband antenna or an ultra- wide band antenna 10 with a frequency at 600-960MHz and 1710-6000MHz.

[00034] In another version, the ultra wideband monopole antenna 10 also operates at 136-174MHz and 380-520MHz (a lower band version of the monopole antenna at 136-174 and 380-520MHz is popular with public safety application for the military, police and/or security force) at the lower band, and 7GHz and beyond at the upper band, or even further at 28GHz band. Scaling is a preferred method to apply a reference antenna design to different band antenna application.

[00035] An obj ect of present invention is to provide an ultra-wideband monopole antenna 10 with a unique arrangement of two quarter wavelength conductors 1 and 2, both having a shape combined from a flat portion la and 2a, and curved wings lb, lc, 2b and 2c.

[00036] FIG. 1 illustrates the ultra-wideband monopole antenna 10 with an arrangement of the first quarter wavelength conductor 1 and second quarter wavelength conductor 2, to provide a 600-960MHz and 1710-6000MHz operating frequency bandwidth.

[00037] FIG. 2 illustrates a top plan view of the ultra- wideband monopole antenna 10 with two identical curved wings lb and lc, 2b and 2c extended from a flat portion la and 2a of each quarter wavelength conductor 1 and 2. The two identical curved wings lb and lc have an equal radius or distance to the center, as do the identical curved wings 2b and 2c. The height of the two identical curved wings lb and lc of the first quarter wavelength conductor 1 preferably ranges from 70mm to 85mm, and is most preferably 78mm. The length of the two identical curved wings lb and lc of the first quarter wavelength conductor 1 preferably ranges from 55mm to 65mm, and is most preferably 60.4mm. The width (or precisely arc length) of the two identical curved wings lb and lc of the first quarter wavelength conductor preferably ranges from 12mm to 20mm, and is most preferably 16.5mm. The thickness of the two identical curved wings lb and lc of the first quarter wavelength conductor 1 preferably ranges from 0.2mm to 0.6mm, and is most preferably 0.4mm. The height of the two identical curved wings 2b and 2c of the second quarter wavelength conductor 2 preferably ranges from 50mm to 65mm, and is most preferably 58.3mm. The length of the two identical curved wings 2b and 2c of the second quarter wavelength conductor 2 preferably ranges from 35mm to 45mm, and is most preferably 39.2mm. The width (or precisely arc length) of the two identical curved wings 2b and 2c of the second quarter wavelength conductor 2 preferably ranges from 7mm to 15mm, and is most preferably 11mm. The thickness of the two identical curved wings 2b and 2c of the second quarter wavelength conductor 2 preferably ranges from 0.2mm to 0.6mm, and is most preferably 0.4mm.

[00038] This ultra-wideband monopole antenna 10 may also comprises additional features necessary for the functionality of a monopole antenna, for example, a ground plane, a coaxial connector or the like, which are not fully described or demonstrated in the following and not shown in the figures.

[00039] Each quarter wavelength conductor 1 and 2 preferably comprises a flat portion edged with two identical curved wings lb and lc, 2b and 2c. The flat portion la of the first quarter wavelength conductor 1 and the flat portion 2a of the second quarter wavelength conductor 2 are preferably arranged and located perpendicular and intersecting to each other.

[00040] There are two identical wings lb and lc, 2b and 2c are connected onto two edges of the flat portion la and 2a of each quarter wavelength conductor 1 and 2, widening the matching bandwidth of the first and second operating frequency.

[00041] Preferably, the identical curved wings lb and lc of the first quarter wavelength conductor 1 and identical curved wings 2b and 2c of the second quarter wavelength conductor 2 are arranged and located concentrically and have a same center.

[00042] As the ultra-wideband monopole antenna preferably has an attractive form factor and aesthetical appearance with an extremely low and slim profile, both the height and the radius have been designed such to match a restricted target. The target height is preferably less than 80mm and the target radius is preferably less than 15mm.

[00043] The pre-determined height of the first quarter wavelength conductor 1, together with two identical curved wings lb and lc, deliver the first operating frequency bandwidth as required for a 5G application.

[00044] Also, the pre-determined diameter of two identical curved wings lb and lc of the first quarter wavelength conductor 1, together with the two identical curved wings 2b and 2c of the second quarter wavelength conductor 2, deliver the first and second operating frequency bandwidth as required for a 5G application.

[00045] FIG. 3 illustrates a return loss of the unique antenna design.

[00046] This unique monopole antenna is arranged such that it not only delivers ultra wideband frequency band, but also generates a flat and linear gain figure plus a high radiation efficiency.

[00047] FIG. 4 illustrates a pre-determined height of flat portions la and 2a from both the first and second quarter wavelength conductors 1 and 2 plus the lengths of the curved wings lb and lc, 2b and 2c from the first and second quarter wavelength conductors 1 and 2, which contribute to the flat and linear gain across the ultra-wideband frequency band.

[00048] FIG. 5 illustrates a peak gain of this monopole antenna in a flat and linear gain figure across the whole operating frequency band. [00049] FIG. 6 illustrates a shape and location of the identical curved wings from the first and second quarter wavelength conductors, which contribute to a high radiation efficiency with an extremely low and slim profile.

[00050] FIG. 7 illustrates a high radiation efficiency of the ultra wideband monopole antenna 10.

[00051] In a cost effective design of the ultra wideband monopole antenna, the ultra wideband monopole antenna also preferably comprises a FR4 PCB as the flat portions la and 2a from the first and second quarter wavelength conductors 1 and 2.

[00052] The flat portions la and 2a, from both the first and second quarter wavelength conductors, are preferably printed on one side of a FR4 PCB 11 and 22 respectively, wherein two printed PCB patterns la and 2a are soldered together perpendicular and intersecting to each other.

[00053] The ultra wideband monopole antenna also preferably comprises a feeding network, such as in a form of coaxial connector 30. The connector 30 preferably comprises a signal feeding portion 31 and a grounding portion 32. As best seen in FIG. 8, the joined patterns of la and 2a are further soldered onto the feeding portion 31, as well as the center conductor of the coaxial connector 30.

[00054] Advantageously, the substrate material of the FR4 PCB provides the mechanical support for the first and second quarter wavelength conductors to be settled down to the body 32 of connector 30. This makes the ultra wideband monopole antenna very cost effective, competitive and easy to be built.