Communication systems and methods of communicating

• US 6,356,535 B1
• Filed: 02/04/1998
• Issued: 03/12/2002
• Est. Priority Date: 02/04/1998
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Smith, Freddie W.
• Primary Examiner(s): Holloway, III, Edwin C.
• Application Number:
  US09/020,595
• Time in Patent Office: 1,497 Days
• Field of Search: 370/278, 455/101, 455/106, 455/107, 342/42-51, 340/10.34, 340/572.1, 340/572.7, 453/78, 453/80, 453/81, 453/129, 453/272, 453/277.1, 343/755, 343/815, 343/834, 343/844, 343/701, 343/700.MS
• US Class Current: 370/278
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07767 the first and second communication means being two different antennas types, e.g. dipole and coil type, or two antennas of the same kind but operating at different frequencies
• CPC Class Codes: G06K 19/07779 the inductive antenna being a coil
• CPC Class Codes: G06K 19/07786 the antenna being of the HF type, such as a dipole
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/241 used in mobile communications, e.g. GSM H01Q1/247, H01Q1/248 take precedence
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 3/247 by switching different parts of a primary active element
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 9/16 with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole H01Q9/44 takes precedence

Abstract

A communication device includes: a first antenna operable to receive wireless communication signals; a second antenna having plural leads, the second antenna operable to output wireless communication signals; a connection including plural conductive lines having respective first ends and second ends, the connection coupled with the leads of the second antenna at the first ends of the lines; and a switch coupled with the second ends of the connection, the switch operable to provide one of selective shorting and isolation of the leads. One method of communicating includes: forming a first antenna; forming a second antenna; receiving wireless interrogation signals using the first antenna; outputting wireless identification signals using the second antenna; opening a coupling intermediate plural leads of the second antenna during the receiving; selectively shorting the leads of the second antenna during the outputting; and providing a low load impedance of the second antenna during the receiving.

Claims

1. A communication system comprising:

an interrogator; and

a communication device configured to communicate with the interrogator, the communication device including;

a first antenna operable to receive wireless communication signals from the interrogator;

a second antenna operable to output wireless communication signals to the interrogator and having a first load impedance and a second load impedance wherein the first load impedance is less than the second load impedance; and

a connection configured to provide the second antenna having the first load impedance less than the second load impedance during receiving of wireless communication signals using the first antenna.

2. The communication system according to claim 1 wherein the first antenna is operable to receive wireless communication signals comprising radio frequency signals and the second antenna is operable to output wireless communication signals comprising radio frequency signals.

3. The communication system according to claim 1 wherein the communication device comprises a radio frequency identification device.

4. The communication system according to claim 1 wherein the communication device further comprises a switch coupled with leads of the second antenna, the switch being open during receiving of wireless communication signals using the first antenna.

5. The communication system according to claim 1 wherein the first antenna and the second antenna are configured to beam form during receiving of the wireless communication signals using the first antenna.

6. The communication system according to claim 1 wherein the first antenna and the second antenna are separated by a distance approximately equal to the wavelength of the wireless communication signals.

7. The communication system according to claim 1 wherein the connection has a length approximately equal to one quarter the wavelength of the wireless communication signals.

8. The communication system according to claim 1 wherein the connection comprises a transmission line.

9. The communication system according to claim 1 wherein the communication device is configured to output wireless communication signals comprising backscatter signals using the second antenna.

10. The communication system according to claim 1 wherein the communication device includes a battery coupled with the first antenna and the second antenna.

11. The communication system according to claim 1 wherein the communication device includes communication circuitry and the second antenna comprises plural leads positioned proximate the communication circuitry and coupled with the communication circuitry and the connection is configured to provide the second antenna having the first load impedance during the presence of a load impendence greater than the first load impedance at the leads.

12. A method of communicating comprising:

forming a first antenna;

forming a second antenna having a first load impedance and a second load impedance wherein the first load impedance is less than the second load impedance;

receiving wireless interrogation signals using the first antenna;

opening a coupling intermediate plural leads of the second antenna during the receiving;

providing the second antenna having the first load impedance less than the second load impedance during the receiving;

outputting wireless identification signals using the second antenna; and

selectively shorting the leads of the second antenna during the outputting.

13. The method according to claim 12 wherein the opening of the coupling and shorting of the leads comprises opening and shorting using a switch.

14. The method according to claim 12 wherein the providing comprises coupling a transformer with the second antenna.

15. The method according to claim 14 wherein the transformer has a length approximately equal to one quarter the wavelength of the wireless communication signals.

16. The method according to claim 12 further comprising beam forming using the first antenna and second antenna during the receiving.

17. The method according to claim 12 further comprising:

processing the wireless interrogation signals; and

generating wireless identification signals responsive to the processing.

18. The method according to claim 12 further comprising spacing the antennas at a length approximately equal to the wavelength of the wireless communication signals.

19. The method of communicating according to claim 12 wherein the outputting comprises outputting wireless identification signals comprising backscatter signals using the second antenna.

20. The method of communicating according to claim 12 wherein the receiving comprises receiving wireless interrogation signals comprising radio frequency signals and the outputting comprises outputting wireless identification signals comprising radio frequency signals.

21. The method according to claim 12 wherein the opening comprises opening the coupling intermediate the plural leads positioned proximate the communication circuitry and the providing comprises providing the second antenna having the first load impedance using a connection intermediate the second antenna and the leads.

22. A method of communicating comprising:

providing a first antenna and a second antenna, the second antenna having a first load impedance and a second load impedance wherein the first load impedance is less than the second load impedance;

receiving wireless communication signals via the first antenna;

outputting wireless communication signals via the second antenna; and

providing the second antenna having the first load impedance less than the second load impedance during the receiving.

23. The method according to claim 22 further comprising opening a coupling intermediate leads of the second antenna during the receiving.

24. The method according to claim 22 further comprising changing between the second load impedance and the first load impedance of the second antenna during the outputting.

25. The method according to claim 22 wherein the providing the second antenna comprises transforming the second load impedance of the second antenna to the first load impedance.

26. The method according to claim 25 wherein the transforming further comprises transforming using a transmission line.

27. The method according to claim 26 wherein the transmission line has a length approximately one quarter the wavelength of the wireless communication signals.

28. The method according to claim 22 further comprising beam forming using the first antenna and second antenna during the receiving.

29. The method according to claim 22 wherein the providing the antennas comprises forming the first antenna apart from the second antenna a distance of about the wavelength of the wireless communication signals.

30. The method of communicating according to claim 22 wherein the outputting comprises outputting wireless identification signals comprising backscatter signals using the second antenna.

31. The method of communicating according to claim 22 wherein the receiving comprises receiving wireless communication signals comprising radio frequency signals and the outputting comprises outputting wireless communication signals comprising radio frequency signals.