WO2010070647A1 - Compact antenna - Google Patents

Abstract

A dual-band dual-mode antenna including a monolithic conductor, the monolithic conductor including an upper portion and a lower portion separated from the upper portion by at least one gap, the monolithic conductor being wrapped around a dielectric core and being adapted to be automatically placed on a printed circuit board.

Description

COMPACT ANTENNA

REFERENCE TO RELATED APPLICATIONS

The present application is related to U.S. Provisional Patent Application Serial No. 61/203,041, filed December 17, 2008, and entitled COMPACT IFA ANTENNA, the disclosure of which is hereby incorporated by reference and priority of which is hereby claimed pursuant to 37 CFR 1.78(a) (4) and (5)(i).

FIELD OF THE INVENTION

The present invention relates generally to antennas and more particularly to dual- mode dual-band antennas adapted for automated printed circuit board (PCB) mounting.

BACKGROUND OF THE INVENTION

The following Patent documents are believed to represent the current state of the art:

U.S. Patents: 6,160,512, 6,177,908, 6,762,723, 6,985,112 and 7,026,994.

SUMMARY OF THE INVENTION

The present invention seeks to provide a compact dual-mode dual-band antenna adapted for automated placement onto a PCB, for use with wireless networking products. The antenna occupies minimal PCB space and is particularly advantageous for use with products having limited PCB to housing clearance.

There is thus provided in accordance with a preferred embodiment of the present invention a dual-band dual-mode antenna including a monolithic conductor, the monolithic conductor including an upper portion and a lower portion separated from the upper portion by at least one gap, the monolithic conductor being wrapped around a dielectric core and being adapted to be automatically placed on a printed circuit board.

In accordance with a preferred embodiment of the present invention, the monolithic conductor operates in a first mode as a monopole antenna conductor.

In accordance with a further preferred embodiment of the present invention, the monolithic conductor operates in a second mode as a slot antenna conductor.

Preferably, the at least one gap includes two vertical gaps contiguous with a horizontal gap.

Preferably, the monolithic conductor includes a ground pin and additional ground pins and is fed by an RF feed pin.

Preferably, the ground pin, additional ground pins and RF feed pin include surface mount technology solder leads.

Alternatively, the ground pin, additional ground pins and RF feed pin include plated thru-hole solder leads.

Preferably, the dielectric core includes plastic and is cylindrical. Alternatively, the dielectric core is rectangular cuboid. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

Fig. 1 is a simplified top view illustration of a flat unformed monolithic antenna conductor constructed and operative in accordance with a preferred embodiment of the present invention;

Fig. 2A is a simplified top view illustration of a compact antenna constructed and operative in accordance with a first preferred embodiment of the present invention, in which the antenna conductor of Fig. 1 is wrapped around a cylindrical dielectric core and includes surface-mount technology (SMT) solder leads;

Fig. 2B is a top view illustration of the PCB footprint of the antenna of Fig. 2 A;

Fig. 3 is a simplified top view illustration of a compact antenna constructed and operative in accordance with a second preferred embodiment of the present invention, in which the antenna conductor of Fig. 1 is wrapped around a cylindrical dielectric core and includes plated thru-hole (PTH) solder leads;

Fig. 4 A a simplified top view illustration of a compact antenna similar to that of Fig. 2A but having a rectangular cuboid dielectric core;

Fig. 4B is a top view illustration of the PCB footprint of the antenna of Fig. 4A;

Fig. 5 is a simplified top view illustration of a compact antenna similar to that of Fig. 3 but having a rectangular cuboid dielectric core;

Fig. 6 is a simplified pictorial illustration of the compact antenna of Fig. 4A being placed by automated placing equipment onto a PCB; and

Fig. 7 is a simplified under-side view illustration of the compact antenna of Fig. 4A in which the antenna includes alignment pins on the base of its dielectric core. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Reference is now made to Fig. 1, which is a simplified top view illustration of a flat unformed monolithic antenna conductor constructed and operative in accordance with a preferred embodiment of the present invention.

As seen in Fig. 1, there is provided an antenna conductor 100, preferably comprising an upper portion 102 and a lower portion 104. Upper and lower portions 102 and 104 are preferably separated by vertical slots 106 and a horizontal slot 108. Preferably contiguous with the lower portion 104 of antenna conductor 100 is a primary ground pin 110 and optional additional ground pins 112. In the embodiment of the antenna shown in Fig. 1, two additional ground pins are illustrated, although more or less are obviously possible. An RF feed pin 114 is provided to feed the antenna conductor 100.

Optional additional ground pins 112 are preferably configurable for impedance matching at different PCB locations, allowing antenna conductor 100 to be easily mounted onto a variety of PCBs.

Reference is now made to Fig. 2A, which is a simplified top view illustration of a compact antenna constructed and operative in accordance with a first preferred embodiment of the present invention, in which the antenna conductor of Fig. 1 is wrapped around a cylindrical dielectric core and includes surface-mount technology (SMT) solder leads.

As seen in Fig. 2A, antenna conductor 200 preferably includes upper portion 202 and lower portion 204 preferably separated by vertical slots 206 and a horizontal slot 208, a primary ground pin 210, optional additional ground pins 212 and an RF feed pin 214.

Antenna conductor 200 is wrapped around a cylindrical dielectric core 220 and preferably mounted substantially perpendicular to the plane of PCB 222. The dielectric core 220 is preferably formed of plastic or any other suitable low permittivity dielectric material. The dielectric core 220 serves to support the antenna conductor 200 and is preferably shaped so as to be compatible with automated component placement equipment, whereby the antenna of the present invention may be easily mounted onto a PCB. For example, the top of dielectric core 220 may be smooth so as to be compatible with the vacuum attachment mechanism used by some types of 'pick and place' automatic placement equipment, or may have features compatible with pincher or claw type jaws employed by other types of automatic placement equipment.

The antenna of the present invention operates in two modes. In its first mode of operation the antenna preferably operates as a monopole, tuned for a first band of operation. The length of upper portion 202 preferably determines the operation frequency of the antenna in this mode.

In its second mode of operation the antenna preferably operates as a slot antenna, tuned for a second band of operation. The lengths of vertical and horizontal slots 206 and 208 separating upper and lower portions 202 and 204 preferably primarily determine the operation frequency of the antenna in this mode. The operation frequency of the antenna in the slot mode is also preferably influenced by the proximity of the open ends of upper and lower portions 202 and 204 to the RF feed pin 214.

The mode and corresponding band of operation of the antenna is preferably selected by the radio device to which the antenna is attached.

Primary ground pin 210, optional additional ground pins 212 and RF feed pin 214 preferably constitute four solder attachment points, providing a strong and reliable connection to PCB 222. In the embodiment shown in Fig. 2, these solder points are in the form of SMT solder leads. The solder leads may extend radially outwards, as illustrated in Fig. 2. Alternatively, the solder leads may be bent under the base of the dielectric core 220 so as to assume a J-lead configuration.

The compact antenna of Fig. 2 has several advantages in addition to those outlined above in reference to the antenna conductor of Fig. 1.

The antenna requires a clearance between the PCB 222 on which it is mounted and the device housing of the order of only 12 mm. This allows the antenna to be easily embedded inside wireless networking products, thereby providing both aesthetic appeal and protection for the antenna.

Furthermore, the antenna of the present invention occupies minimal space on the PCB 222. The compact nature of the antenna may be appreciated from Fig. 2B, which is a top view illustration of the PCB footprint of the antenna of Fig. 2A. As seen in Fig. 2B, the PCB footprint 230 comprises four rectangular regions 232, 234, 236 and 238 corresponding respectively to the four solder attachment points provided by the primary ground pin 210, two optional additional ground pins 212 and RF feed pin 214.

A further advantage of the compact antenna of the present invention is that it does not require a ground deletion region beneath it. Electronics components and associated printed wiring traces may therefore be located in the vicinity of the antenna, allowing the PCB surface to be utilized more densely and therefore more efficiently.

In addition, the compact antenna of Fig. 2 preferably comprises only two parts, namely a single piece antenna conductor 200 and dielectric core 220. Its manufacture is therefore relatively simple and inexpensive.

Reference is now made to Fig. 3, which is a simplified top view illustration of a compact antenna constructed and operative in accordance with a second preferred embodiment of the present invention, in which the antenna conductor of Fig. 1 is wrapped around a cylindrical dielectric core and includes plated thru-hole (PTH) solder leads.

As seen in Fig. 3, antenna conductor 300 preferably includes upper portion 302 and lower portion 304 preferably separated by vertical slots 306 and horizontal slot 308, primary ground pin 310, optional additional ground pins 312 (only one of which is visible in Fig. 3) and an RF feed pin 314. Antenna conductor 300 is wrapped around cylindrical dielectric core 320 and preferably mounted substantially perpendicular to the plane of PCB 322.

The compact antenna of Fig. 3 shares all of the features and advantages of the compact antenna of Fig. 2 A, with the structural difference that the primary ground pin 310, ground pins 312 and RF feed pin 314 are preferably in the form of PTH solder leads rather than SMT solder leads, as shown in the embodiment of Fig. 2A.

Reference is now made to Figs. 4 A - 5, which are respectively a simplified top view illustration of a compact antenna similar to that of Fig. 2A but having a rectangular cuboid dielectric core, the antenna's PCB footprint and a simplified top view illustration of a compact antenna similar to that of Fig. 3 but having a rectangular cuboid dielectric core.

The antennas shown in Figs. 4A - 5 differ from the respective antennas and their footprint shown in Figs. 2A - 3 only in the shape of the dielectric cores 400 and 500 and their corresponding dielectric footprint 410, which dielectric cores are preferably in the form of rectangular cuboids rather than cylinders. It is appreciated that in addition to the cylindrical and rectangular cuboid dielectric cores described and illustrated herein, differently shaped dielectric cores are also within the scope of the present invention.

Reference is now made to Figs. 6 and 7 which are respectively a simplified pictorial illustration of the compact antenna of Fig. 4A being placed by automated placing equipment onto a PCB and a simplified under-side view illustration of the antenna of Fig. 4A in which the antenna includes alignment pins on the base of its dielectric core

As seen in Figs. 6 and 7, compact antenna 600 is placed by automated equipment 602 onto a PCB 604, prior to soldering. Antenna 600 is preferably mounted substantially perpendicular to the plane of the PCB. Antenna 600 may be supplied in a packaging compatible with the feeding system of automated placing equipment 602, such as in tape and reel or in plastic rail packaging. Antenna 600 may also include extra features to ensure its correct installation, such as alignment pins 700 on the base of its dielectric core. The alignment pins 700 are designed to fit mating holes 702 in PCB 704 and thus decrease the chance of incorrect installation of the antenna.

It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly claimed hereinbelow. Rather the scope of the present invention includes various combinations and subcombinations of the features described hereinabove as well as modifications and variations thereof as would occur to persons skilled in the art upon reading the foregoing description with reference to the drawings and which are not in the prior art.

Claims

1. A dual-band dual-mode antenna comprising: a monolithic conductor, said monolithic conductor comprising: an upper portion; a lower portion, separated from said upper portion by at least one gap; said monolithic conductor being wrapped around a dielectric core and being adapted to be automatically placed on a printed circuit board.

2. The antenna of claim 1, wherein said monolithic conductor operates in a first mode as a monopole antenna conductor.

3. The antenna of claims 1 or 2, wherein said monolithic conductor operates in a second mode as a slot antenna conductor.

4. The antenna of any of claims 1 - 3, wherein said at least one gap comprises two vertical gaps contiguous with a horizontal gap.

5. The antenna of claim 1, wherein said monolithic conductor includes a ground pin.

6. The antenna of claim 5, wherein said monolithic conductor includes additional ground pins.

7. The antenna of claim 6, wherein said monolithic conductor is fed by an RF feed pin.

8. The antenna of claim 7, wherein said ground pin, additional ground pins and RP feed pin comprise surface mount technology solder leads.

9. The antenna of claim 7, wherein said ground pin, additional ground pins and RF feed pin comprise plated thru-hole solder leads.

10. The antenna of any of the preceding claims, wherein said dielectric core comprises plastic.

11. The antenna of claim 10, wherein said dielectric core is cylindrical.

12. The antenna of claim 10, wherein said dielectric core is rectangular cuboid.