Low-band dipole with extended bandwidth and improved mid-band masking

Abstract

A low band dipole for a dense multiband antenna array has a plurality of dipole arms. The dipole arm has a coupling plate disposed on a first side of a PCB and a conductive trace pattern disposed on a second side of the PCB. The conductive trace pattern has a plurality of resonator block structures coupled together by a phase shift trace along a first edge of the conductive trace pattern and a bandwidth compensation disposed along a second edge of the conductive trace pattern.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a non-provisional application of and claims the benefit of priority to pending U.S. Provisional Patent Application No. 63 / 339,086, filed on May 6, 2022, which is incorporated herein by reference in its entirety as if fully set forth herein. Technical Field

[0003] The present invention relates to wireless communications and, more particularly, to low-band (LB) dipoles for use in multi-band antennas. Background Art

[0004] The proliferation of many new frequency bands in cellular communications has increased the demand for antennas that operate in multiple frequency bands. There is also increased pressure to keep the antenna footprint small so that wind loading of the antenna is not exacerbated and so that the antenna takes up minimal space in dense urban environments. These opposing requirements place considerable pressure on antenna designers to place antenna dipoles for different frequency bands in closer proximity to each other, thereby exacerbating inter-band interference and secondary radiation, which degrades antenna performance.

[0005] The LB dipoles, being the largest of the dipoles within a multi-band antenna, are subject to the most inter-band interference because they are the largest and a densified multi-band antenna dipole layout requires the arms of the LB dipole to extend over and overlap the mid-band (MB) and C-band dipoles. Conventional masking techniques exist to mitigate MB coupling and secondary radiation in LB dipoles, but there are limits to the effectiveness of conventional techniques. For example, a conventional LB dipole may be designed to operate in a frequency range of 617-894 MHz. However, there is a need for the LB dipole to operate in lower frequencies, thereby extending the LB frequency range so that the desired LB range is 617-894 MHz, where conventional masking techniques do not prevent interference at this wide frequency range extending into the low frequencies.

[0006] Therefore, what is needed is a LB dipole design that is effectively transparent in the mid-frequency band from 617-894 MHz and can be positioned in close proximity to the MB dipole to meet antenna densification requirements. Summary of the invention

[0007] One aspect of the present disclosure relates to a low-band dipole for a multi-band antenna. The low-band dipole includes a balun stem; and a plurality of dipole arms mechanically coupled to the balun stem, wherein each of the dipole arms has a printed circuit board (PCB) substrate, a coupling plate disposed on a first side of the PCB substrate, and a conductive trace pattern disposed on a second side of the PCB substrate, wherein the conductive trace pattern has a plurality of resonator block structures, each of adjacent resonator block structures being coupled by a phase shift trace and a bandwidth compensation trace.

[0008] Another aspect of the present disclosure relates to a low-band dipole for a multi-band antenna. The low-band dipole includes a balun guide; and a plurality of dipole arms mechanically coupled to the dipole guide, wherein each of the dipole arms includes: a plurality of resonator members; a member for phase shifting disposed between adjacent resonator members; and a member for bandwidth compensation disposed between adjacent resonator members. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0010] Figure 1 An exemplary array of LB dipoles to be integrated into a multi-band antenna is shown.

[0011] Figure 2 An exemplary LB dipole according to the present disclosure is shown.

[0012] Figure 3 Show Figure 2 An exemplary dipole of is contemplated to be in close proximity to a subarray deployment of MB dipoles.

[0013] Figure 4 Show Figure 1 and 2 An exemplary LB dipole with the guide removed.

[0014] Figure 5A Exemplary dipole arms of a LB dipole according to the present disclosure are shown.

[0015] Figure 5B Show Figure 5A Exemplary dipole arms of an LB dipole, which are referenced for additional details. DETAILED DESCRIPTION

[0016] Figure 1An exemplary array 100 of LB dipoles 105 to be integrated into a multi-band antenna is shown. The array 100 has five exemplary LB dipoles 105 arranged in vertical columns and mechanically coupled to a reflector plate 110. Not shown are MB dipoles to be deployed in the array in close proximity to the LB dipoles 105 of the array 100.

[0017] Figure 2 An exemplary LB dipole 105 according to the present disclosure is shown. The LB dipole 105 has four LB dipole arms 205 arranged in a cross pattern. The LB dipole arms 205 are mechanically and electrically coupled to balun guides 215, which in turn are coupled to a feed plate 220, which is mechanically coupled to a reflector plate 110. Also shown is a guide plate 210, which is disposed above the four LB dipole arms 205 and can be mechanically mounted above the four dipole arms using a non-conductive clip or base structure (not shown). The function of the guide plate is to widen the bandwidth of the four LB dipole arms 205.

[0018] Figure 3 An exemplary LB dipole 105 is shown mounted in close proximity to a subarray of MB dipoles 305, with the director plate 210 removed for purposes of illustration. As shown, the dipole arms 205 of the LB dipole 105 extend over and thus shield the MB dipoles 305. Given the diagonal orientation of the LB dipole arms 205, it is generally not feasible to place the LB dipole 105 in close proximity to multiple MB dipoles 305 without such shielding. Therefore, it is important to design the LB dipole 105 so that its dipole arms 205 are effectively transparent to the MB energy emitted by the MB dipoles 305.

[0019] Figure 4 An exemplary LB dipole 105 is shown with the guide plate 210 removed for purposes of illustration. The LB dipole 105 has four dipole arms 205, each of which is disposed as a conductive trace pattern 410 on the underside of a printed circuit board (PCB) 402 (shown in outline). The conductive trace pattern 410 may be formed from a single piece of 1.4 mil thick copper, and the PCB 402 may be formed from, for example, 30 mil thick FR4 material. Disposed on the upper surface of the PCB 402 are four coupling plates 415, one for each dipole arm 205. Each of the four coupling plates 415 is directly coupled to a feed trace ( 414 ) on the balun guide 215 via a corresponding solder joint 425. Figure 44. A). Each coupling plate 415 capacitively couples to its corresponding dipole arm 205 across the dielectric of PCB 402. Capacitively coupling the coupling plates 415 to the corresponding dipole arms 205 improves the bandwidth performance of the LB dipole 105. The impedance of the LB dipole 105 can be tuned by adjusting the size of the coupling plates 415 to adjust the width of the gaps 430 between the coupling plates 415. Each dipole arm 205 has a high gain wing-shaped trace 420 disposed on either side. The high gain wing-shaped trace 420 increases the volume of its corresponding dipole arm 205 and thus increases the gain of the LB dipole 105.

[0020] Figure 5A One of the exemplary dipole arms 205 of the LB dipole 105 according to the present disclosure is shown. The dipole arm 205 is formed by a conductive trace pattern 410 having three repeating resonator block structures 505 (the center resonator block structure 505 is indicated in the figure) disposed on the PCB 402. As shown in FIG. 5, the exemplary conductive trace pattern 410 may have a width W1 of 20.93 mm, and a length L1 of 96.16 mm; and the coupling plate 415 may have a width W2 of 24.39 mm, and a length L2 of 24.94 mm. In addition, the high gain wing-shaped trace 420 has a first segment 420 that may have a width of 0.7 mm, a second parallel segment 420b that may have a width of 1.175 mm, and a third segment that may have a width of 0.475 mm. The combined width W3 of the high gain wing-shaped trace 420 and the conductive trace pattern 410 may be equal to 37.6 mm. It should be understood that these dimensions are exemplary and that variations are possible and within the scope of the present disclosure.

[0021] Figure 5B 505. The same view of the dipole arm 205 is shown, but with further detail of one of the resonator block structures 505. The resonator block structure 505 has a rectangular pattern of gaps 510 interrupted by bridges 515 that define an inner portion and an outer portion of the block structure 505. The inner portion of the resonator block structure 505 can be square with a dimension of 14.39 mm on each side. In an exemplary embodiment, the gap 510 can have a width of, for example, 0.76 mm. The resonator block structure 505 is coupled to its adjacent resonator block structure 505 by two traces: a phase shift trace 520 and a bandwidth compensation trace 530 (both at Figure 5B). The phase shift trace 520 and the bandwidth compensation trace 530 may be disposed on opposite edges of the conductive trace pattern 410. The phase shift trace 520 has a meandering portion 525 that increases the path length of the phase shift trace 520 to achieve a 180 degree phase shift of the radio frequency (RF) current flowing in the conductive trace pattern 410 between adjacent resonator block structures 505. The phase shift trace 520 may have a path length of 31.2 mm, a trace width of 0.781 mm, and a separation of 0.698 mm. The phase shift trace 520 may be disposed in a first gap 535 between adjacent resonator block structures 505, the first gap being wider than a second gap 555 between adjacent resonator block structures 505. The first gap 550 may have a width of 3.72 mm, and the second gap 555 may have a width of 1.8 mm. It should be understood that the dimensions provided herein are exemplary, and variations are possible and within the scope of the present disclosure.

[0022] The bandwidth compensation trace 530 has a thin line step 535 that provides a high impedance between the resonator block structure 505 and its adjacent resonator block structure 505 to help make the dipole arm 250 transparent to the MB frequency and prevent MB resonance. The bandwidth compensation trace 530 can have a path length of 17.3 mm and a width of 0.781 mm; and the thin line step 535 can have a width of 0.381 mm. It should be understood that these dimensions are exemplary and variations are possible and within the scope of the present disclosure.

[0023] The resonator mass structure 505 further has a decoupling structure 540, which may be formed by gaps in the outer portion of the resonator mass structure 505 and tab protrusions from the inner portion of the resonator mass structure. The decoupling structure 540 helps prevent MB resonances from occurring in the dipole arms 205.

[0024] The resonator block structure 505 further has a pair of decoupling slots 545 that simply mirror the geometry of the gap between the bandwidth compensation trace 530 and adjacent exterior portions of the resonator block structure 505 .

[0025] The disclosed exemplary LB dipole 105 has the advantage that it prevents MB radiation from inducing currents within the conductive trace pattern 410 that might otherwise re-radiate and interfere with the performance of the nearby MB dipole 305. Furthermore, the disclosed structure for the LB dipole arms provides high performance in the lower range of the low frequency band: extending down to 617 MHz, while substantially preventing MB resonance.

[0026] Although various embodiments of the present invention have been described above, it should be understood that they are presented as examples rather than limitations. It will be apparent to those skilled in the relevant art that various changes may be made in form and detail without departing from the spirit and scope of the present invention. Therefore, the breadth and scope of the present invention should not be limited to any of the exemplary embodiments described above, but should only be limited according to the appended claims and their equivalents.

Claims

1. A low-band dipole for a multi-band antenna, comprising: Balun guide rods; as well as a plurality of dipole arms mechanically coupled to the balun guides, wherein each of the dipole arms has a printed circuit board (PCB) substrate, a coupling plate disposed on a first side of the PCB substrate, and a conductive trace pattern disposed on a second side of the PCB substrate, wherein The conductive trace pattern has a plurality of resonator block structures, each of adjacent resonator block structures being coupled by a phase shifting trace and a bandwidth compensating trace. 2 . The low-band dipole of claim 1 , wherein the phase-shifting trace is disposed along a first edge of the conductive trace pattern and the bandwidth-compensating trace is disposed along a second edge of the conductive trace pattern.

3. A low frequency band dipole according to claim 1 or claim 2, wherein the phase shift trace comprises The twisty part.

4. The low-band dipole of claim 3, wherein the phase shift trace further comprises a path length configured to impart a 180 degree phase shift to mid-band radio frequency (RF) oscillations induced in the conductive trace pattern.

5. A low-band dipole according to any one of the preceding claims, wherein the bandwidth compensation trace comprises a thin line step in the bandwidth compensation trace disposed between two adjacent resonator block structures, the thin line step having a width that is less than a width of the bandwidth compensation trace.

6. A low-band dipole according to any one of the preceding claims, wherein each resonator mass structure has a plurality of gaps defining an inner portion and an outer portion, wherein two adjacent gaps are separated by a bridging portion.

7. A low-band dipole as claimed in claim 6, wherein each resonator mass structure comprises a decoupling structure.

8. The low-band dipole of claim 7, wherein the decoupling structure comprises: a gap formed in the outer portion of the resonator mass structure; as well as A tab protrusion is disposed in the gap formed in the outer portion of the resonator mass structure, wherein the tab protrusion is continuous with the inner portion of the resonator mass structure.

9. A low-band dipole according to any one of the preceding claims, wherein the coupling plate is directly coupled to balun traces disposed on the balun guides.

10. The low-band dipole of claim 9, wherein the coupling plate is capacitively coupled to the conductive trace pattern.

11. A low-band dipole for a multi-band antenna, comprising: Balun guide rods, and a plurality of dipole arms mechanically coupled to the dipole guide, wherein each of the dipole arms comprises: a plurality of resonator members; means for phase shifting disposed between adjacent resonator members; and A means for bandwidth compensation is disposed between the adjacent resonator means.

Images