TW201505264A - Dual broadband circular polarization monopole antenna - Google Patents

Abstract

A dual broadband circular polarization monopole antenna comprises a radiating element and a feeding element. The radiating element includes a main body radiator element having a piercing slot, and a coupling perturbation plate outwardly extended from the main body radiator element. The feeding element includes two grounding plates separated from each other, a feed plate located between the two grounding plates, a coupling plate extended from the feed plate and positively projecting at least a portion onto the coupling perturbation plate in the direction of the radiating element, wave limiting plates extended from the coupling plate, and a cut slot formed toward the direction of the coupling plate from the top edge of the wave limiting sheet that is away from the coupling plate. The positive projection of the wave limiting plates and the cut slot toward the direction of the radiating element at least partially falls on the main body radiator element. With incorporation of the radiating element and the cut slot of the feeding element, the invention generates dual frequency band bandwidth respectively achieving above 11% and 8.5%.

Description

Double wide frequency circularly polarized monopole antenna

The invention relates to a dual frequency antenna, in particular to a double wide frequency circularly polarized monopole antenna

When the polarization direction of the electromagnetic wave is different from the polarization direction of the receiving antenna, the receiving dead angle is easily formed, and the path of the electromagnetic wave is usually non-linear, so that the transmission process generates a multipath interference effect due to encountering many obstacles, in order to To reduce the above problems, a circularly polarized antenna is a better choice. In addition, in order to be applied to the Global Navigation Satellite System (GNSS) and the International Maritime Satellite (INMARSAT) operating band, the whole frequency is divided into two bands of 1164~1300MHz and 1525MHz~1660.5MHz, which needs to be designed. A dual-frequency circularly polarized antenna with a circular polarization bandwidth of 11% and 8.5% relative to each other.

See "Novel Broadband Monopole Antennas With Dual-Band Circular Polarization," IEEE Transactions on Antennas and Propagation, Vol. 57, No. 4, pp. 1027-1034, April. The antennas have a circular polarization bandwidth of 5.6% and 23.1%, respectively, and the bandwidths of the two are too different, and the low frequency bandwidth of 5.6% does not reach the required standard of 11%.

Accordingly, it is an object of the present invention to provide a dual wide frequency circularly polarized monopole antenna having a dual frequency circular polarization bandwidth of 11% and 8.5%, respectively.

Thus, the dual wide frequency circularly polarized monopole antenna of the present invention comprises a radiating element and a feed element.

The radiating element is formed on a first plane and includes a main body radiating sheet having a through slot, and a coupled perturbation sheet extending outward from the main body radiating sheet.

The feed element is formed on a second plane and includes a two-phase spacing and grounding piece for grounding, a feed piece between the two grounding plates, and a direction extending from the feeding piece and facing the radiating element a positive projection of a coupling piece at least partially falling on the coupling perturbation piece, a wave limiting piece extending from the coupling piece, and a dividing groove formed from the top edge of the limiting plate away from the top edge of the coupling piece toward the coupling piece And the orthographic projection of the wave limiting plate and the dividing groove toward the radiating element at least partially falls on the main body radiating sheet.

The effect of the present invention is that the radiating element transmits and receives a circularly polarized RF signal, and the feeding element couples the RF signal with the radiating element, and divides the bandwidth into a double bandwidth by the dividing slot of the feeding component, and The radiating element and the feeding element correspond to each other such that the double-bandwidth of the double-wideband circularly polarized monopole antenna can reach 11% and 8.5%, respectively, and the circularly polarized RF signal is further purified.

1‧‧‧radiation components

11‧‧‧Main Radiation

111‧‧‧Circular circumference

112‧‧‧Long diameter

12‧‧‧coupled perturbation

13‧‧‧through slot

131‧‧‧ outer edge

132‧‧‧ inner edge

2‧‧‧Feed components

21‧‧‧First grounding piece

22‧‧‧Second grounding piece

23‧‧‧Feed

24‧‧‧ coupling piece

25‧‧‧Limitor

251‧‧‧Top edge

26‧‧‧Segmentation slot

3‧‧‧ dielectric substrate

31‧‧‧ first plane

32‧‧‧ second plane

4‧‧‧reflecting elements

41‧‧‧ bottom wall

42‧‧‧ Surrounding wall

421‧‧‧ wall height

Other features and effects of the present invention will be apparent from the following description of the drawings. FIG. 1 is a plan view showing a first preferred embodiment of the dual wide frequency circularly polarized monopole antenna of the present invention. 1 is a bottom view, FIG. 2 is a bottom view, and FIG. 1 is a view showing the first preferred embodiment in a second plane; FIG. 3 is a side view, and FIG. 1 is a side view illustrating the double broadband of the present invention. The first preferred embodiment of the circularly polarized monopole antenna; FIG. 4 is an experimental measurement diagram illustrating the return loss of the first preferred embodiment; FIG. 5 is an experimental measurement diagram illustrating the first comparison The circular polarization axis ratio of the preferred embodiment; FIG. 6 is a perspective view showing a second preferred embodiment of the dual wide frequency circularly polarized monopole antenna of the present invention; FIG. 7 is an experimental measurement diagram illustrating the second comparison The return loss of the preferred embodiment; FIG. 8 is an experimental measurement diagram illustrating the circular polarization axis ratio of the second preferred embodiment; FIG. 9 is an experimental measurement diagram illustrating the operation of the second preferred embodiment at 1200 MHz. Radiation pattern of time; and FIG. 10 is an experimental measurement diagram illustrating that the second preferred embodiment operates at 1525M Radiation pattern at Hz.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to FIG. 1 , FIG. 2 and FIG. 3 , a first preferred embodiment of the dual wide frequency circularly polarized monopole antenna of the present invention comprises a radiating element 1 made of a conductor and transmitting and receiving circularly polarized RF signals. A feed element 2 for electrically and inductively exchanging RF signals with the radiating element, and a dielectric substrate 3 for the radiating element 1 and the feed element 2, respectively.

When the feeding component 2 exchanges the RF signal with the radiating component 1, the radiating component 1 simultaneously generates a first linear polarization and a second linear polarization to synthesize a circular polarization mode. The first linear polarization direction is defined as x, and the second linear polarization direction is y.

The dielectric substrate 3 includes a first plane 31 and a second plane 32 which are opposite and parallel to each other. The radiating element 1 is disposed on the first plane 31, and the feeding element 2 is of a coplanar waveguide feeding type. It is disposed on the second plane 32. In the first preferred embodiment, the dielectric substrate 3 is a rectangular parallelepiped having a length, a width, and a height of 105, 68, and 1.6 mm, a dielectric constant ε _r of 4.4, and a tangent loss of 0.02.

The radiating element 1 includes a main body radiating sheet 11 having a through slot 13 and a coupled perturbation sheet 12 extending outward from the main body radiating sheet 11. In the first preferred embodiment, the main body radiating sheet 11 is substantially semi-circular with a radius of 20 mm and the long side 112 of the diameter is perpendicular to the first linear polarization direction x. The coupled perturbation sheet 12 is substantially rectangular and extends from a circular arc periphery 111 of the main body radiating sheet 11, and the coupled perturbation sheet 12 is away from the main body radiating sheet 11 The side line is parallel to the long side 112 of the main body of the main body radiating sheet 11, and has a length of 16 mm, and the other side of the coupled perturbation sheet 12 has a length of 14 mm. The through slot 13 is formed into a semicircular arc shape having a width fixed to 8 mm, and is symmetric with respect to a center line perpendicular to the long side 112 of the diameter of the main body radiating sheet 11, and an outer edge 131 of the through slot 13 and the main body radiating piece The arcuate circumference 111 of the 11 is equidistant, and an inner edge 132 of the through slot 13 is parallel to the two sides of the second linear polarization direction y to a distance of the long side 112 of the main body radiation sheet 11 by a distance of 3 mm. The circular arc of 132 is at a center distance of 9 mm from the main body radiation sheet 11. The main body radiation sheet 11 changes the surface current distribution of the main body radiation sheet 11 by the through grooves 13 to produce more favorable circular polarization characteristics.

The feed element 2 includes a first grounding strip 21 spaced apart and used for grounding, a second grounding strip 22, a feed piece 23 located between the first grounding strip 21 and the second grounding strip 22, and a feed element a coupling piece 24 extending from the feeding piece 23, a wave limiting piece 25 extending from the coupling piece 24, and a direction from the top edge 251 of the wave limiting piece 25 away from the coupling piece 24 toward the coupling piece 24 Split slot 26.

In the first preferred embodiment, the first grounding strip 21 and the second grounding strip 22 of the feeding element 2 are substantially rectangular, and form an asymmetric five with the feeding piece 23 for feeding. a ten-ohm coplanar waveguide, and the lengths of the first grounding strip 21 and the second grounding strip 22 are different, the two sides of the first grounding strip 21 are 67 and 17 mm, respectively, and the two sides of the second grounding strip 22 are respectively It is 32, 17 mm, and the distance between the first grounding piece 21 and the second grounding piece 22 from the feeding piece 23 is 0.5 mm. The feed piece 23 extends in a direction perpendicular to the long side 112 of the diameter of the main body radiation sheet 11. The rectangle is parallel to the side of the main body of the radiation sheet 11 in the direction of the long side 112 of the diameter of 5 mm, and the other side line is 18.5 mm. The coupling piece 24 is formed in a rectangular shape extending parallel to the long side 112 of the diameter of the main body radiation piece 11. The orthographic projection of the coupling piece 24 in the direction of the radiating element 1 at least partially falls on the coupling perturbation piece 12, and Falling into the main body radiation sheet 11 and having one side line tangential to the circular arc peripheral edge 111 of the main body radiation piece 11, the side of the coupling piece 24 parallel to the diameter long side 112 of the main body radiation piece 11 is 25 mm, and The other side line is 12.5 mm. Therefore, the energy fed from the feed piece 23 can be coupled to the coupled perturbation piece 12 via the coupling piece 24 and transmitted to the main body radiation piece 11.

The wave limiting plate 25 has a rectangular shape extending in a direction perpendicular to the long side 112 of the diameter of the main body radiating sheet 11, and the orthographic projection in the direction of the radiating element 1 completely falls onto the main body radiating sheet 11, and the wave limiting plate 25 The orthographic projection of the top edge 251 is aligned with the long side 112 of the main body of the radiation piece 11, the edge of the wave-limiting plate 25 parallel to the long side 112 of the main body of the radiation piece 11 is 5 mm, and the other side is 20 Millimeter. The dividing groove 26 extends into a portion of the coupling piece 24, and the orthographic projection in the direction of the radiating element 1 at least partially falls onto the main body radiating sheet 11, and the dividing groove 26 divides the limiting plate 25 into two parts. . The dividing groove 26 has a feature of cutting a frequency band such that the single frequency band becomes a dual frequency band, and the circumference of the dividing groove 26 is one-half of a spatial wavelength corresponding to a double frequency cutting frequency. In the first preferred embodiment, the wave limiting sheets 25 divided into two by the dividing groove 26 are spaced apart from each other by 1 mm, and the length of the dividing groove 26 extending toward the coupling piece 24 is 31 mm.

Referring to FIG. 4, in order to actually measure the return loss map of the first preferred embodiment, the return loss is greater than 10 dB in the frequency bands 1097 MHz to 1418 MHz and 1420 MHz to 2000 MHz, and the application range is 1164 to 1300 MHz and 1525 MHz to 1660.5 MHz. Included in the frequency band of this design.

Referring to FIG. 5, in order to actually measure the circular polarization axis ratio of the first preferred embodiment, in the frequency bands 1134 MHz to 1391 MHz and 1460.5 MHz to 1719 MHz, the axial ratios are all less than 3 dB, and the required frequency band ranges are included herein. In the design, the center frequency of 1134MHz~1391MHz is 1262.5MHz, the converted circular polarization bandwidth is 20.4%, the center frequency of 1460.5MHz~1719MHz is 1589.8MHz, and the converted circular polarization bandwidth is 16.3%. . Therefore, the first preferred embodiment confirms that it is possible to achieve 11% or more of the target bandwidth by actual measurement.

Referring to FIG. 1 , FIG. 2 and FIG. 6 , a second preferred embodiment of the dual wide frequency circularly polarized monopole antenna of the present invention is similar to the first preferred embodiment, except that the second preferred embodiment further A conductive material is formed and provided for the dielectric substrate 3, the radiating element 1, and the reflective element 4 in which the feeding element 2 is disposed.

The reflective element 4 includes a bottom wall 41 parallel to and spaced apart from the second plane 32 of the dielectric substrate 3, and a surrounding extending from the periphery of the bottom wall 41 along the second plane 32 toward the first plane 31. Wall 42. For convenience of explanation, the direction of the second plane 32 to the first plane 31 is defined as the z direction. The distance from the second plane 32 of the dielectric substrate 3 to the bottom wall 41 is equal to the wall height 421 of the surrounding wall 42, and the distance from the periphery of the dielectric substrate 3 to the surrounding wall 42 is equal to the wall height 421, the wall Height 421 is the double wide frequency circle A center frequency of a polarized monopole antenna corresponds to a quarter of a free-space wavelength. In the second preferred embodiment, the frequency band that has not been added to the reflective element 4 ranges from 1134 MHz to 1391 MHz and 1460.5 MHz to 1719 MHz, and the center frequency of 1134 MHz and 1719 MHz is 1426.5 MHz.

The reflecting element 4 is disposed such that the wall height 421 is a quarter of the free space wavelength corresponding to the center frequency, so that the RF signal generated by the radiating element 1 and the feeding element 2 hits the bottom wall. The reflected wave of 41 is a constructively enhanced radio frequency signal in the z direction, so that the second preferred embodiment can obtain a larger radiation gain in the z direction, and is confirmed by actual measurement, the second preferred embodiment The unidirectional (z-direction) radiation gain is substantially increased by about 6 dBic compared to the bidirectional (z-direction and -z-direction) radiation gains after removal of the reflective element 4, and the maximum gain in the applied band is about 9.4 dBic, so The second preferred embodiment is more suitable for applications requiring high directivity characteristics.

Referring to FIG. 7, in order to actually measure the return loss map of the second preferred embodiment, the return loss is greater than 10 dB in the frequency band 1045 MHz to 2000 MHz, and the second preferred embodiment includes the reflective element. 4 will not cause a reduction in impedance bandwidth.

Referring to FIG. 8, in order to actually measure the circular polarization axis ratio of the second preferred embodiment, in the frequency bands 1120 MHz to 1389 MHz and 1449 MHz to 1786 MHz, the axial ratio is less than 3 dB, and the center frequency of 1120 MHz to 1389 MHz is 1254.5 MHz. Then, the converted circular polarization bandwidth is 21.4%, and the center frequency of 1449 MHz to 1786 MHz is 1617.5 MHz, and the converted circular polarization bandwidth is 20.8%. Confirmed by actual measurement, the second best The embodiment includes that the reflective element 4 also does not cause a reduction in the circular polarization bandwidth.

Referring to Figures 9 and 10, there is shown a radiation pattern of the second preferred embodiment, Figure 9 is a radiation pattern measured at a frequency of 1200 MHz, and Figure 10 is a radiation pattern measured at a frequency of 1525 MHz. 9 and 10 show that the reflective element 4 can suppress radiation in the -z direction by 20 dB, thereby greatly increasing the z-direction radiation gain.

Therefore, the reflective element 4 can not only destroy the original impedance bandwidth and the circular polarization bandwidth without changing the aspect size of the radiating element 1, the feeding element 2, and the dielectric substrate 3, but instead The RF signal in the -z direction is reflected back to the z direction, and is constructively superimposed with the RF signal in the z direction, and the surrounding wall 42 of the reflective element 4 narrows the beam width of the RF signal, so that the second preferred embodiment The one-way radiation gain is greatly improved.

It should be noted that the dielectric constant and the tangential loss of the dielectric substrate 3 are not limited, and the size of the radiating element 1 and the feeding element 2 can be matched with the dielectric substrate 3, and the adjustment is slightly adjusted. The circular polarization characteristics are similar. Similarly, the size of the radiating element 1 and the feeding element 2 can be slightly adjusted according to actual conditions.

In summary, the dual wideband circularly polarized monopole antenna of the present invention transmits and receives a circularly polarized RF signal through the radiating element 1, and the feeding component 2 is coupled to the radiating element 1 for exchanging RF signals. The feeding component The dividing groove 26 of 2 divides the required dual frequency band, and the radiation element and the feeding element are opposite to each other such that the feeding element 2 and the radiating element 1 generate the same bilinear polarization direction, so that the two circular poles The bandwidth can reach 20% and 16% respectively, and can be further used by the reflective element 4 without affecting the circular polarization bandwidth. Next, the unidirectional radiation gain is increased to achieve a circular polarization bandwidth of 11% and 8.5% or more of the double-wideband circularly polarized monopole antenna, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

1‧‧‧radiation components

11‧‧‧Main Radiation

12‧‧‧coupled perturbation

13‧‧‧through slot

2‧‧‧Feed components

21‧‧‧First grounding piece

22‧‧‧Second grounding piece

23‧‧‧Feed

24‧‧‧ coupling piece

25‧‧‧Limitor

26‧‧‧Segmentation slot

Claims (9)

A dual wide frequency circularly polarized monopole antenna comprising: a radiating element formed on a first plane and comprising a body radiating plate having a through slot, and a coupled perturbation piece extending outward from the body radiating plate And a feed element formed on a second plane and including a two-phase spacing and grounding grounding strip, a feed piece between the grounding strips, an extension from the feeding piece and toward the radiation An orthographic projection of the component direction at least partially falls into the coupling piece on the coupled perturbation piece, a wave limiting plate extending from the coupling piece, and a direction from the top edge of the limiting plate away from the coupling piece toward the coupling piece The dividing groove, the orthographic projection of the wave limiting plate and the dividing groove in the direction of the radiating element at least partially falls on the main body radiating sheet. The dual wide frequency circularly polarized monopole antenna according to claim 1, further comprising a dielectric substrate including the first plane and the second plane, wherein the first plane and the second plane are parallel to each other. The double-wideband circularly-polarized monopole antenna according to claim 2, wherein the main body radiating fin is substantially semicircular, the coupled perturbation sheet is substantially rectangular, and the coupled perturbation sheet is from a circle of the main body radiating sheet The circumference of the arc extends and an edge away from the radiating sheet of the body is parallel to the long side of the diameter of the main body radiating sheet. The double-wideband circularly-polarized monopole antenna according to claim 3, wherein the through-groove is formed into a semi-circular arc shape having a uniform width, and is symmetric with respect to a center line perpendicular to a long side of a diameter of the main body radiating sheet, and is worn An outer edge of the slot is equidistant from a circumference of the arc of the body radiating sheet. The double wide frequency circularly polarized monopole antenna according to claim 4, wherein the feed The electric piece has a rectangular shape extending in a direction perpendicular to a longitudinal direction of a diameter of the main body radiation piece, and the coupling piece has a rectangular shape extending in a direction parallel to a longitudinal direction of a diameter of the main body radiation piece. The double-wideband circularly-polarized monopole antenna according to claim 5, wherein the orthographic projection of the coupling piece in the direction of the radiating element does not fall on the main body radiating piece, and the one side line and the arc circumference of the main body radiating piece Tangent. The double-wideband circularly-polarized monopole antenna according to claim 6, wherein the wave-limiting plate has a rectangular shape extending perpendicular to a longitudinal direction of a diameter of the main body radiation piece, and an orthographic projection toward the radiating element is completely dropped. The orthographic projection of the top edge of the main body of the radiating sheet is aligned with the long side of the main body of the radiating sheet. The dual wide-band circularly-polarized monopole antenna according to claim 7, wherein the dividing groove extends inwardly to a part of the coupling piece, and the circumference of the dividing groove is a space corresponding to a double-frequency cutting frequency One-half of the wavelength. The double-wideband circularly-polarized monopole antenna according to claim 8, further comprising a conductive material for the dielectric substrate, the radiating element, and the reflective element disposed therein, the reflective element comprising a parallel a bottom wall spaced apart from a second plane of the dielectric substrate, and a surrounding wall extending from the periphery of the bottom wall along the second plane toward the first planar direction, the second plane of the dielectric substrate to the bottom wall The distance is equal to the wall height of the surrounding wall, the distance from the periphery of the dielectric substrate to the surrounding wall is equal to the wall height, and the wall height is a free space corresponding to a center frequency of the double wide frequency circularly polarized monopole antenna One quarter of the spatial wavelength.