GB2404497A - PCB mounted antenna - Google Patents

Abstract

A printed circuit board (PCB) 2 mounted antenna comprises a radiating element 1 formed from a single piece of metal which is integrated with support and feed members 11, 12. The radiating element 1 may be stamped or etched from a single piece of metal and may be in the form of a planar inverted F antenna, a meander line or straight monopole or dipole arrangement. The feed and support members 11, 12 may be arranged to form part of the radiating structure, tune the antenna resonant frequency, provide impedance matching to the antenna and/or adjust the bandwidth of the antenna. The support and feed members 11, 12 may be arranged for solder mounting in a hole or on the surface of the circuit board 2. Multiple radiating elements may be employed to cover multiple bandwidths. The radiating element may include a meander line with varying pitch to cover different frequencies. The radiating element 1 may be tuned by the cutting of the said radiating element 1. The antenna may include a dielectric cover or loading members 15, 16. This arrangement provides a compact antenna structure which is readily manufactured and directly attached to a circuit board which may be mounted inside a device requiring an antenna.

Description

PCB MOUNTED ANTENNA

This invention relates generally to the field of antennas for wireless communication devices ireiess communication devices such as personal digital assistants, mobile phones, wireless modems, tracking devices, telemetric devices etc. More particularly, the present invention relates to a meander line antenna that is mounted directly to the devices' printed circuit board (PCB).

Background

Antenna devices are increasingly being mounted internally to the radio units fitted directly to the device PC13. This has been driven by the improved infrastructure of base stations, radio module performance, cost considerations and aesthetic considerations.

The drive for lower costs has resulted h1 a need for a shnple, low cost, antenna solution.

Summary of the invention

Tile object of this invention is to provide a low cost antenna, which can be attached directly to the l'C13 of the radio unit.

According to a broad aspect of the invention there is provided an antenna for coupling to a printed circuit board, the antenna comprising of a metal radiating element and at least two mounting pins connected to the radiating element. 'I'he radiated element is electrically connected to the mounting pins to form a composite radiating structure. Tile pins have four- fold function: to radiate electromagnetic waves as part of a composite radiating structure, to tune the antenna resonant frequency, to improve antenna input impedance match and bandwidth and to provide means of connecting the antenna to the printed circuit hoard.

Additionally a cover or dielectric loading can be incorporated.

These and other objectives, features and advantages of the present invention, will he apparent to those skilled in the art.

Detailed Description ofthe Ilivention

A preferred embodiment of the invention will now be described with rel'ereoce to the accompanying drawings ha which: Figure I shows a general arrangement Figure 2 shows a variation of the pins for surface mount applications Figure 3 shows an application with the radiating element horizontal Figure 4 shows applications with single row radiating element and additional radiating element giving dual band operation Figure 5 shows application with a multiple row radiating element Figure 6 shows an application with a dipole radiating element Figure 7 shows an application with an Inverted F Figure 8 shows an application with a PIFA radiating element A stamped or etched metal radiating element (1) is attached directly onto the host printed circuit board (2) by the placement of'feed pin (11) and support ph1 (12) through teed hole (21) and support hole (22) respectively. The pins (11&12) are soldered into the holes (21&22). Shoulders (I la & 12a) may be provided to raise the radiating element (1) from the surface of the printed circuit board (2). For surface mount applications the pins (17 & 18) could be bent at an appropriate angle as shown in figure 2. for this application more than 2 pins may be required for stability. The feed pin (11) is heed from a feed line (23) connecting to the radio module of the device. The radiating element (1) is shown in a vertical position this may be altered for other applications t'or example in a horizontal mode as shown in figure 3 where the shoulders (I l la & 112a) are increased in height to raise the radiating element (100) above the printed circuit board (200).

The radiating element (1) is made from an appropriate material such as brass or steel and can be plated with a suitable material such a tin to enable a good solder joint. As shown h1 figure I tile radiating element (1) consist of two rows of meander lines (13a & 13b) connected by a connecting bar (14) this allows a shorter antenna where space is restricted.

I'he radiating element (1) could equally consist of a shigle row (30) or multiple rows (40) as shown in figure 4. The radiating element (1) is shown as a monopole antenna relying on the ground plane of the printed circuit board (2) to complete the antenna, however by providing two elements as shown in figure 5 a dipole antenna (50) can be made.

Tuning of the radiating element (1) can be achieved by varying the pitch and height of the meander lines (13a & 13b), the overall length of the radiating element (1) and also by cutting the length of meander line (13b) beyond the support ph1 (12) thus varying the length (15). 'I'he size shape and position of the pins (11 &12) and the connecting bar (14) can also be used to tune the antemia. Dielectric material can be incorporated h1 the form of an internal dielectric (15) and/or a cover (16).1'he internal dielectric (15) could be in the form of a suitable block of material clipped, glued or otherwise attached to the radiating element (1) or in the form of an encapsulant to attach to the cover (16). The radiating element (1) could also be over-moulded with a suitable dielectric material such as a thermoplastic or thermoses polymer or ceramic thus combining the functions of both the internal dielectric (15) and the cover (16).

Multiple resonances can be achieved by having varyhig pitches or by the addition of an extra radiating element (31) as show in figure 4.

It follows that straight radiating elements could be used in place of meander lines (13a & 13h) as illustrated with the dipole antenna (50). Also Inverted F (60) and planar inverted F (PlFAs) (70) could also be produced using this invention.

Claims (16)

1. A pch mounted antenna made from a single stamped or etched metal part comprising a meander line radiating element and integral support and feed legs.

2. A pcb mounted antenna as claimed in C'lahn I where the antenna is mounted on through holes on the pcb.

3. A pcb mounted antenna as clawed in Claim I where the antenna is surface mounted holes on the pcb.

4. A pcb mounted antenna as claimed in Claims I to 3 where the antenna can be tuned by cutting the radiating element.

5. A pcb mounted antenna as claimed in Claims I to 4 where the antenna can resonate at two or more frequencies by having varying pitches on the meander line.

6. A pcb mounted antenna as claimed in Claims I to 5 where the antenna can resonate at two or more frequencies by having an extra radiating element

7. A pcb mounted antenna as claimed in Claims I to 6 where the radiating element is straight.

8. A pcb mounted antenna as claimed he Claims I to 7 where the radiating element comprises more than one row.

9. A pcb mounted antenna as claimed in Claims I to 8 where the radiating element is an inverted F.

1 O. A pcb mounted antenna as claimed in Claims I to 9 where the radiating element is a Planar Inverted F.

11. A pcb mounted antenna as claimed in Claims 1 to 10 where the radiating element is at any angle to the pcb.

12. A pcb mounted antenna as claimed in Claims I to 11 where the radiating element is in any way covered in a dielectric material.

13. A pcb mounted antenna as claimed h1 Claims I to 12 where more than one radiating element is used to provide a dipole antenna.

14. A pcb mounted antenna as claimed in Claims I to 13 where the support pins are used as a tuning element.

15. A pcb mounted antenna as claimed in Claims 1 to 14 where connecting bars can be used as tuning elements.

16. A PC13 mounted Antenna substantially as herein described and illustrated in the accompanying drawings.