COMPACT, UNIPLANAR DIFFERENTIAL-FED TRANSPARENT FILTENNA

Abstract

Provided is a compact, uniplanar differential-fed transparent filtenna, comprising a dielectric substrate, and a metal ground plane attached to the dielectric substrate, wherein an avoidance slot is formed in the metal ground plane. A circular radiator is further attached to the dielectric substrate, a ring slot is formed in the circular radiator, shorting stubs are attached to the dielectric substrate on the two sides of the circular radiator, and the shorting stubs on the two sides are respectively connected to the ends of coplanar waveguide differential feedlines attached to the dielectric substrate on the two sides, and the other ends of the coplanar waveguide differential feedlines on the two sides are respectively connected to inner conductors of differential coaxial cables located on the side wall of the dielectric substrate, and outer conductors of the differential coaxial cables are connected to a bottom plate of the metal ground plane.

Claims

1. A compact, uniplanar differential-fed transparent filtenna, comprising a dielectric substrate (1), and a metal ground plane (2) attached to the dielectric substrate (1), wherein an avoidance slot (3) is formed in the metal ground plane (2); a circular radiator (4) is further attached to the dielectric substrate (1), a ring slot (5) is formed in the circular radiator (4), and shorting stubs (6) are attached to the dielectric substrate (1) at two sides of the circular radiator (4); the shorting stubs (6) on the two sides are respectively connected to the ends of coplanar waveguide differential feedlines (7) attached to the dielectric substrate (1) on the two sides, the other ends of the coplanar waveguide differential feedlines (7) on the two sides are respectively connected to inner conductors of differential coaxial cables (8) located on the side wall of the dielectric substrate (1), and outer conductors of the differential coaxial cables (8) are connected to a bottom plate of the metal ground plane (2); and the circular radiator (4), the shorting stubs (6) and the coplanar waveguide differential feedlines (7) are all located in the avoidance slot (3).

2. The compact, uniplanar differential-fed transparent filtenna according to claim 1, wherein the circular radiator (4) is attached to the center position of the upper surface of the dielectric substrate (1), the ring slot (5) divides the circular radiator (4) into an inside circular annular radiating patch (41) and an outside circular annular radiating patch (42); the shorting stubs (6) each comprise a fan-shaped circular ring (61) and two rectangular lugs (62) connected to both ends of the fan-shaped circular ring (61), the other ends of the two rectangular lugs (62) are connected to the metal ground plane (2), and the central axis of the fan-shaped circular ring (61) coincides with the central axis of the circular radiator (4); and the coplanar waveguide differential feedline (7) is rectangular, the projection of the lengthwise central axis of the coplanar waveguide differential feedline (7) in a vertical direction coincides with the projection of the lengthwise central axis of the dielectric substrate (1) in a vertical direction, and one end of the coplanar waveguide differential feedline (7) is connected to the middle of the fan-shaped circular ring (61).

3. The compact, uniplanar differential-fed transparent filtenna according to claim 2, wherein the avoidance slot (3) comprises a circular avoidance slot (31) for avoiding the circular radiator (4) and the shorting stubs (6), and stepped avoidance slots (32) located on the two sides of the circular avoidance slot (31) for avoiding the coplanar waveguide differential feedlines (7); each stepped rectangular slot (32) comprises a first rectangular avoidance slot (321), one end of the first rectangular avoidance slot is connected to the circular avoidance slot (31), and the other end of the first rectangular receding slot (321) is connected to one end of a second rectangular avoidance slot (322); and the second rectangular avoidance slot (322) penetrates through the metal ground plane (2); and the central axis of the circular avoidance slot (31) coincides with the central axis of the circular radiator (4), and the lengthwise central axes of the first rectangular avoidance slot (321) and the second rectangular avoidance slot (322) coincide with the lengthwise central axis of the coplanar waveguide differential feedline (7).

4. The compact, uniplanar differential-fed transparent filtenna according to claim 1, wherein the metal ground plane (2), the circular radiator (4), the shorting stub (6) and the coplanar waveguide differential feedline (7) each are made of a copper mesh.

5. The compact, uniplanar differential-fed transparent filtenna according to claim 4, wherein the copper mesh has a thickness d of 2 μm, a line width L of 5 μm, and a line spacing W of 70 μm.

6. The compact, uniplanar differential-fed transparent filtenna according to claim 3, wherein the dielectric substrate (1) is made of Coming Eagle-XG glass with a relative dielectric constant of 5.27, a loss tangent tan of 0.001, a length sub-1 of 43 mm, a width sub-w of 33 mm, and a thickness H of 0.5 mm; a spacing S.sub.1 between the fan-shaped circular ring (61) and the circular avoidance slot (31) is 0.6 mm; a spacing S.sub.2 between the circular annular radiating patch (42) and the fan-shaped circular ring (61) is 1.4 mm, the circular radiator (4) has a radius R.sub.2 of 11.2 mm, the circular annular radiating patch (41) has a radius R.sub.1 of 7.1 mm, and the ring slot (5) has a width S.sub.3 of 0.3 mm; the coplanar waveguide differential feedline (7) has a width W.sub.1 of 2.4 mm; the first rectangular avoidance slot (321) has a width W.sub.2 of 6.4 mm, and the second rectangular avoidance slot (322) has a width W.sub.3 of 5.1 mm; and the fan-shaped circular ring (61) and the rectangular lug (62) each have a width W.sub.4 of 0.7 mm, and the fan-shaped circular ring (61) as a fan-shaped included angle a of 163°.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings of the present disclosure are described as follows.

[0027] FIG. 1 is a three-dimensional view of an antenna structure in accordance with the present disclosure;

[0028] FIG. 2 is a top view of an antenna structure in accordance with the present disclosure;

[0029] FIG. 3 is a top view of a metal mesh employed by an antenna structure in accordance with the present disclosure;

[0030] FIG. 4 illustrates a relationship between a sheet resistance of a metal mesh structure employed by an antenna structure and a frequency in accordance with the present disclosure;

[0031] FIG. 5 is a plot of differential mode reflection coefficients |S.sub.dd11| and the frequency for the antenna in accordance with the present disclosure;

[0032] FIG. 6 is a plot of an overall efficiency and the frequency for the antenna in accordance with the present disclosure;

[0033] FIG. 7 is a plot of a realized gain and frequency for the antenna in accordance with the present disclosure;

[0034] FIG. 8 illustrates radiation patterns of the E plane and the H plane of the antenna in accordance with the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The present disclosure is further described below with reference to the accompanying drawings and the embodiments.

[0036] In the drawings and this disclosure the following reference numbers designate the following elements: 1—dielectric substrate; 2—metal ground plane; 3—avoidance slot; 31—circular avoidance slot; 32—stepped avoidance slot; 321—first rectangular avoidance slot; 322—second rectangular avoidance slot; 4—circular radiator; 41—circular annular radiating patch; 42—circular annular radiating patch; 5—ring slot; 6—shorting stub; 61—fan-shaped circular ring; 62—rectangular lug; 7—coplanar waveguide differential feedline; 8—differential coaxial cable.

[0037] In the description of the embodiments of the present disclosure, it needs to be understood that the orientation or positional relationship indicated by terms “center”, “longitudinal”, “transverse”, “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside” and “outside ” is based on the orientation or positional relationship shown in the drawings only for convenience of description of the present disclosure and simplification of description rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and thus are not to be construed as limiting the present disclosure. Furthermore, the terms “first”, “second” and “third” are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying a number of the indicated technical features. In the description of the embodiments of the present disclosure, it needs to be noted that, unless expressly specified and limited otherwise, the terms “connected,” “connection,” should be understood broadly, e.g., either fixed connection, detachable connection, or integral connection; either mechanical connection or electrical connection; either direct connection or indirect connection via an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in embodiments of the present disclosure should be understood in specific cases.

[0038] As shown in FIG. 1 to FIG. 3, a compact, uniplanar differential-fed transparent filtenna, comprises a dielectric substrate 1, and a metal ground plane 2 attached to the dielectric substrate 1, where an avoidance slot 3 is formed in the metal ground plane 2.

[0039] A circular radiator 4 is further attached to the dielectric substrate 1, a ring slot 5 is formed in the circular radiator 4, and shorting stubs 6 are attached to the dielectric substrate 1 at two sides of the circular radiator 4. The shorting stubs 6 on the two sides are respectively connected to the ends of coplanar waveguide differential feedlines 7 attached to the dielectric substrate 1 on the two sides, the other ends of the coplanar waveguide differential feedlines 7 on the two sides are respectively connected to inner conductors of differential coaxial cables 8 located on the side wall of the dielectric substrate 1, and outer conductors of the differential coaxial cables 8 are connected to a bottom plate of the metal ground plane 2.

[0040] The circular radiator 4, the shorting stubs 6 and the coplanar waveguide differential feedlines 7 are all located in the avoidance slot 3.

[0041] As an embodiment of the present disclosure, the circular radiator 4 is attached to the center position of the upper surface of the dielectric substrate 1. The ring slot 5 divides the circular radiator 4 into an inside circular annular radiating patch 41 and an outside circular annular radiating patch 42.

[0042] The shorting stubs 6 each comprise a fan-shaped circular ring 61 and two rectangular lugs 62 connected to the two ends of the fan-shaped circular ring 61, and the other ends of the two rectangular lugs 62 are connected to the metal ground plane 2. The central axis of the fan-shaped circular ring 61 coincides with the central axis of the circular radiator 4.

[0043] The coplanar waveguide differential feedline 7 is rectangular. The projection of the lengthwise central axis of the coplanar waveguide differential feedline 7 in a vertical direction coincides with the projection of the lengthwise central axis of the dielectric substrate 1 in a vertical direction, and one end of the coplanar waveguide differential feedline 7 is connected to the middle of the fan-shaped circular ring 61.

[0044] As an embodiment of the present disclosure, the avoidance slot 3 comprises a circular avoidance slot 31 for avoiding the circular radiator 4 and the shorting stubs 6, and stepped avoidance slots 32 located on the two sides of the circular avoidance slot 31 for avoiding the coplanar waveguide differential feedlines 7. Each stepped rectangular slot 32 comprises a first rectangular avoidance slot 321, one end of the first rectangular avoidance slot 321 is connected to the circular avoidance slot 31, and the other end of the first rectangular receding slot 321 is connected to one end of a second rectangular avoidance slot 322. The second rectangular avoidance slot 322 penetrates through the metal ground plane 2.

[0045] The central axis of the circular avoidance slot 31 coincides with the central axis of the circular radiator 4. The lengthwise central axes of the first rectangular avoidance slot 321 and the second rectangular avoidance slot 322 coincide with the lengthwise central axis of the coplanar waveguide differential feedline 7.

[0046] As an embodiment of the present disclosure, the metal ground plane 2, the circular radiator 4, the shorting stubs 6 and the coplanar waveguide differential feedlines 7 each are made of a copper mesh.

[0047] In accordance with this embodiment, the copper mesh is used to realize the transparency of the antenna. As shown in FIG. 4, a sheet resistance of 0.15 Ω/square is obtained for a waveguide simulation result of the copper mesh to be adopted. In the simulation of the antenna, the sheet resistance values of sheets of the coplanar waveguide differential feedline 7, the shorting stub 6, the circular radiator 4 and the metal ground plane 2 are set to be 0.15 ohm for simulation.

[0048] As an embodiment of the present disclosure, the copper mesh has a thickness d of 2 μm, a line width L of 5 μm, and a line spacing W of 70 μm.

[0049] As an embodiment of the present disclosure, the dielectric substrate 1 is made of Corning Eagle-XG glass with a relative dielectric constant of 5.27, a loss tangent tan of 0.001, a length sub-1 of 43 mm, a width sub-w of 33 mm, and a thickness H of 0.5 mm.

[0050] A spacing S.sub.1 between the fan-shaped circular ring 61 and the circular avoidance slot 31 is 0.6 mm.

[0051] A spacing S.sub.2 between the circular annular radiating patch 42 and the fan-shaped circular ring 61 is 1.4 mm.

[0052] The circular radiator 4 has a radius R.sub.2 of 11.2 mm, the circular annular radiating patch 41 has a radius R.sub.1 of 7.1 mm, and the ring slot 5 has a width S.sub.3 of 0.3 mm.

[0053] The coplanar waveguide differential feedline 7 has a width W.sub.1 of 2.4 mm.

[0054] The first rectangular avoidance slot 321 has a width W.sub.2 of 6.4 mm, and the second rectangular avoidance slot 322 has a width W.sub.3 of 5.1 mm.

[0055] The fan-shaped circular ring 61 and the rectangular lug 62 each have a width W.sub.4 of 0.7 mm, and the fan-shaped circular ring 61 as a fan-shaped included angle a of 163°.

[0056] Based on above parameters, the high frequency structure simulator (HFSS) is used to perform simulated analysis on the performance parameters, such as reflection coefficients |S.sub.11|, overall efficiency, gains and patterns of the designed compact uniplanar differential-fed transparent filtenna, with analysis results as follows:

[0057] As shown in FIG. 5, the antenna has a −10 dB bandwidth of 3.17 GHz to 3.92 GHz, and an impedance bandwidth up to 21.16%.

[0058] As shown in FIG. 6, the antenna has an overall radiation efficiency of 60% and more.

[0059] As shown in FIG. 7, the antenna has a peak realized gain of 2.18 dBi, and three radiation nulls are generated on the two edges of the operating band, which makes the antenna have sharp roll-off rates and high out-of-band suppression level.

[0060] As shown in FIG. 8, the cross-polarization level of the antenna is extremely low.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure rather than limiting the same. Although the present disclosure has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that modifications or equivalent substitutions may still be made to specific embodiments of the present disclosure, and that any modification or equivalent substitution that does not depart from the spirit and scope of the present disclosure shall be encompassed within the scope of the claims of the present disclosure.