Wireless communication RF circuit and communication apparatus including the same

• US 7,133,641 B2
• Filed: 04/23/2003
• Issued: 11/07/2006
• Est. Priority Date: 04/23/2002
• Status: Expired due to Fees

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Yamaguchi, Yoshihiro, Ieki, Tsutomi
• Primary Examiner(s): Nguyen, Duc M.
• Application Number:
  US10/497,513
• Publication Number:
  US 20050176381A1
• Time in Patent Office: 1,294 Days
• Field of Search: 455/41.1, 455/41.2, 455/42, 340/10.1, 340/10.3, 340/10.4, 340/825.58, 340/825.7, 340/825.77
• US Class Current: 455/41.1
• 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: H04B 1/44 Transmit/receive switching
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence

Abstract

A wireless communication RF circuit includes a transmitting-and-receiving antenna, a modulator circuit, an SPST switching circuit, and a demodulator circuit, which are arranged in a sequence. Upon signal reception, the SPST switching circuit is switched ON, and the demodulator circuit extracts a signal wave from a signal received by the antenna and outputs the signal wave to a control circuit. Upon signal transmission, the SPST switching circuit is switched OFF, and the modulator circuit mixes transmission data supplied from the control circuit with a carrier and outputs the carrier to the antenna. Only a single antenna is required. Upon signal reception, the influence of the modulator circuit is negligible. Upon signal transmission, the SPST switching circuit is switched OFF, thus the effect of the demodulator circuit is negligible, which greatly reduces loss.

Claims

1. A wireless communication radio frequency circuit comprising:

an antenna that transmits and receives radio waves;

a demodulator circuit that detects a received radio wave received by the antenna and extracts a signal wave; and

a modulator circuit that mixes a signal wave supplied from a signal feeder with a carrier;

wherein

the antenna, the modulator circuit, and the demodulator circuit are serially connected to one another in a sequence;

a Single Pole Single Throw switching circuit is serially connected directly between the modulator circuit and the demodulator circuit;

the Single Pole Single Throw switching circuit is switched ON upon reception to transmit a signal received by the antenna to the demodulator circuit and is switched OFF upon transmission to separate the demodulator circuit from the modulator circuit; and

the Single Pole Single Throw switching circuit includes an FET.

2. A wireless communication radio frequency circuit according to claim 1, wherein the demodulator circuit is one of an AM detector circuit that demodulates a received radio wave having an amplitude that has been modulated and an Amplitude Shift Keying detector circuit that demodulates a received radio wave that has been Amplitude shift Keying-modulated.

3. A wireless communication radio frequency circuit according to claim 1, wherein the demodulator circuit includes a zero-bias detector Schottky barrier diode.

4. A wireless communication radio frequency circuit according to claim 1, wherein the modulator circuit includes an FET.

5. A wireless communication radio frequency circuit according to claim 1, wherein the modulator circuit is a binary phase shift keying modulator circuit.

6. A wireless communication radio frequency circuit according to claim 1, wherein an amplitude-adjusting resistor for adjusting the amplitude of a wave modulated by the modulator circuit is connected in parallel with at least one of the Single Pole Single Throw switching circuit and the modulator circuit.

7. A wireless communication radio frequency circuit according to claim 1, wherein the modulator circuit includes a phase adjuster.

8. A wireless communication radio frequency circuit according to claim 1, wherein the antenna is a microstrip patch antenna, and the microstrip patch antenna, the modulator circuit, the SPST switching circuit, and the demodulator circuit are arranged on a common dielectric board, the dielectric board having a relative dielectric constant of at least about 10.

9. A communication apparatus comprising a wireless communication radio frequency circuit according to claim 1.

10. A communication apparatus according to claim 9, wherein the communication apparatus is a transponder that receives a radio wave emitted from an interrogator, mixes a signal wave with the received radio wave, and reflectively transmits the resulting radio wave to the interrogator.

11. A wireless communication radio frequency circuit comprising:

an antenna that transmits and receives radio waves;

a demodulator circuit that detects a received radio wave received by the antenna and extracts a signal wave; and

a modulator circuit that mixes a signal wave supplied from a signal feeder with a carrier;

wherein

the antenna, the modulator circuit, and the demodulator circuit are serially connected to one another in a sequence;

a Single Pole Single Throw switching circuit is serially connected between the modulator circuit and the demodulator circuit;

the Single Pole Single Throw switching circuit is switched ON upon reception to transmit a signal received by the antenna to the demodulator circuit and is switched OFF upon transmission to separate the demodulator circuit from the modulator circuit;

the Single Pole Single Throw switching circuit includes an FET; and

the modulator circuit is a reflective modulator circuit that modulates the phase of the signal received by the antenna in accordance with the signal wave and reflectively transmits the modulated signal.

12. A wireless communication radio frequency circuit comprising:

an antenna that transmits and receives radio waves;

a demodulator circuit that detects a received radio wave received by the antenna and extracts a signal wave; and

a modulator circuit that mixes a signal wave supplied from a signal feeder with a carrier;

wherein

the antenna, the modulator circuit, and the demodulator circuit are serially connected to one another in a sequence; and

a Single Pole Single Throw switching circuit is serially connected directly between the modulator circuit and the demodulator circuit.

13. A wireless communication radio frequency circuit according to claim 12, wherein the Single Pole Single Throw switching circuit is switched ON upon reception to transmit a signal received by the antenna to the demodulator circuit and is switched OFF upon transmission to separate the demodulator circuit from the modulator circuit.

14. A wireless communication radio frequency circuit according to claim 12, wherein the Single Pole Single Throw switching circuit includes an FET.

15. A wireless communication radio frequency circuit according to claim 12, wherein the demodulator circuit is one of an AM detector circuit that demodulates a received radio wave having an amplitude that has been modulated and an Amplitude Shift Keying detector circuit that demodulates a received radio wave that has been Amplitude Shift Keying-modulated.

16. A wireless communication radio frequency circuit according to claim 12, wherein the demodulator circuit includes a zero-bias detector Schottky barrier diode.

17. A wireless communication radio frequency circuit according to claim 12, wherein the modulator circuit includes an FET.

18. A wireless communication radio frequency circuit according to claim 12, wherein the modulator circuit is a reflective modulator circuit that modulates the phase of the signal received by the antenna in accordance with the signal wave and reflectively transmits the modulated signal.

19. A wireless communication radio frequency circuit according to claim 12, wherein the modulator circuit is a binary phase shift keying modulator circuit.

20. A wireless communication radio frequency circuit according to claim 12, wherein an amplitude-adjusting resistor for adjusting the amplitude of a wave modulated by the modulator circuit is connected in parallel with at least one of the Single Pole Single Throw switching circuit and the modulator circuit.

21. A wireless communication radio frequency circuit according to claim 12, wherein the modulator circuit includes a phase adjuster.

22. A wireless communication radio frequency circuit according to claim 12, wherein the antenna is a microstrip patch antenna, and the microstrip patch antenna, the modulator circuit, the SPST switching circuit, and the demodulator circuit are arranged on a common dielectric board, the dielectric board having a relative dielectric constant of at least about 10.

23. A communication apparatus comprising a wireless communication radio frequency circuit according to claim 12.

24. A communication apparatus according to claim 23, wherein the communication apparatus is a transponder that receives a radio wave emitted from an interrogator, mixes a signal wave with the received radio wave, and reflectively transmits the resulting radio wave to the interrogator.