EM SHIELD FOR INTERNAL ANTENNA OF HANDHELD TERMINALS

• US 20110261551A1
• Filed: 04/23/2010
• Published: 10/27/2011
• Est. Priority Date: 04/23/2010
• Status: Active Grant

• Current Assignee: Psion Inc (Zebra Technologies Corporation)
• Original Assignee: Psion Inc (Zebra Technologies Corporation)
• Inventors: Roy, Iain Campbell, Chirila, Laurian Petru
• Granted Patent: US 8,339,807 B2
• Time in Patent Office: Days
• US Class Current: 361/818
• CPC Class Codes: G06K 7/10168 the powering being adversely affected by environmental influences, e.g. unwanted energy loss in the interrogation signal due to metallic or capacitive objects in the proximity of the interrogation device or in the proximity of the interrogated record carrier
• CPC Class Codes: G06K 7/10386 the interrogation device being of the portable or hand-handheld type, e.g. incorporated in ubiquitous hand-held devices such as PDA or mobile phone, or in the form of a portable dedicated RFID reader
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/526 Electromagnetic shields
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

A portable terminal having a plurality of electronic components and an antenna such that at least a portion of the plurality of electronic components and the antenna are housed internally by a housing. The terminal comprising a first enclosure of the housing having a first interior to contain the plurality of electronic components and a ground. The terminal has a second enclosure of the housing for coupling to the first enclosure, the second enclosure having a second interior to contain the antenna and for facilitating at least one of receiving or transmitting of EM signals between the antenna and an environment external to the second enclosure. The terminal has an electromagnetic (EM) shield positioned at an interface between the first interior and the second interior, the EM shield including electrically conductive material to absorb EM radiation generated by the plurality of electronic components being directed towards the antenna and to convert at least a portion of the absorbed EM radiation into electrical current and direct the electrical current towards the ground of the first enclosure. Also included is an electrically conductive coupling to couple the EM shield to the ground of the first enclosure.

Claims

1. A portable terminal having a plurality of electronic components and an antenna such that at least a portion of the plurality of electronic components and the antenna are housed internally by a housing, the terminal comprising:

a first enclosure of the housing having a first interior to contain the plurality of electronic components and a ground;

a second enclosure of the housing for coupling to the first enclosure, the second enclosure having a second interior to contain the antenna and for facilitating at least one of receiving or transmitting of EM signals between the antenna and an environment external to the second enclosure;

a electromagnetic (EM) shield positioned at an interface between the first interior and the second interior, the EM shield including electrically conductive material to absorb EM radiation generated by the plurality of electronic components being directed towards the antenna and to convert at least a portion of the absorbed EM radiation into electrical current and direct the electrical current towards the ground of the first enclosure; and

a electrically conductive coupling to couple the EM shield to the ground of the first enclosure.

2. The terminal of claim 1 further comprising a feed line for connecting at least one of a receiver or a transmitter of the plurality of electrical components to the antenna.

3. The terminal of claim 2, wherein the feed line passes through the interface via a hole or slot in the EM shield.

4. The terminal of claim 1, wherein the electrically conductive coupling is a resilient coupling configured to maintain electrical contact between the ground and the EM shield in the event of mechanical vibration or shock delivered to the housing.

5. The terminal of claim 4, wherein the resilient coupling is an electrically conductive gasket.

6. The terminal of claim 4, wherein the resilient coupling is a metallic biased member.

7. The terminal of claim 1, wherein EM shield is mechanically attached to the first enclosure at the interface.

8. The terminal of claim 7, wherein EM shield is mechanically attached to the second enclosure at the interface.

9. The terminal of claim 1 further comprising mounts in the interior of the second housing for positioning the antenna a predefined distance away from a facing surface of the EM shield.

10. The terminal of claim 9, wherein the EM shield is selected from the group consisting of:

a rigid plate and a flexible plate.

11. A method for assembling a portable terminal having a plurality of electronic components and an antenna such that at least a portion of the plurality of electronic components and the antenna are housed internally by a housing, the method comprising the steps of:

installing the plurality of electronic components in a first interior of a first enclosure of the housing, the first enclosure having a ground;

installing the antenna in a second interior of a second enclosure of the housing, the second enclosure for facilitating at least one of receiving or transmitting of EM signals between the antenna and an environment external to the second enclosure;

positioning a electromagnetic (EM) shield at an interface between the first interior and the second interior, the EM shield including electrically conductive material to absorb EM radiation generated by the plurality of electronic components being directed towards the antenna and to convert at least a portion of the absorbed EM radiation into electrical current and direct the electrical current towards the ground of the first enclosure;

attaching an electrically conductive coupling to the EM shield for coupling the EM shield to the ground of the first enclosure; and

fastening the second enclosure and the first enclosure to one another.

12. The method of claim 11 further comprising the step of attaching a feed line to connect at least one of a receiver or a transmitter of the plurality of electrical components to the antenna.

13. The method of claim 12, wherein the feed line passes through the interface via a hole or slot in the EM shield.

14. The method of claim 11, wherein the electrically conductive coupling is a resilient coupling configured to maintain electrical contact between the ground and the EM shield in the event of mechanical vibration or shock delivered to the housing.

15. The method of claim 14, wherein the resilient coupling is an electrically conductive gasket.

16. The method of claim 14, wherein the resilient coupling is a metallic biased member.

17. The method of claim 11, wherein EM shield is mechanically attached to the first enclosure at the interface prior to fastening the first enclosure to the second enclosure.

18. The method of claim 17, wherein EM shield is coupled to the electrically conductive coupling when the second enclosure and the first enclosure are fastened to one another.

19. The method of claim 11 further comprising the step of mounting in the interior of the second housing the antenna in a predefined distance away from a facing surface of the EM shield.

20. The method of claim 19, wherein the EM shield is selected from the group consisting of:

a rigid plate and a flexible plate.