RF antenna coupling structure

• US 6,919,858 B2
• Filed: 10/10/2003
• Issued: 07/19/2005
• Est. Priority Date: 10/10/2003
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Rofougaran, Ahmadreza (Reza)
• Primary Examiner(s): Chen, Shih-Chao
• Assistant Examiner(s): Tran, Chuc
• Application Number:
  US10/683,185
• Publication Number:
  US 20050090287A1
• Time in Patent Office: 648 Days
• Field of Search: 343/850, 343/795, 343/700.MS, 343/749, 343/822, 343/750, 343/852, 343860-861, 455/333, 455/552.1, 455/292, 455/252.1, 455/83, 455/129, 455/78, 455/284, 455/340, 455/425
• US Class Current: 343/850
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H

Abstract

An RF antenna coupling structure includes a first transformer, a second transformer, and a transformer balun. The first transformer includes a primary winding and a secondary winding, wherein the primary winding of the first transformer is operably coupled to a power amplifier, and wherein the secondary winding of the first transformer has a desired output impedance corresponding to the operational needs of the power amplifier. The second transformer includes a primary winding and a secondary winding, wherein the primary winding of the second transformer is operably coupled to a low noise amplifier, and wherein the secondary winding of the second transformer has a desired output impedance corresponding to the needs of the low noise amplifier. The transformer balun includes a differential winding and a single-ended winding, wherein the differential winding is operably coupled to the secondary windings of the first and second transformers and the single-ended winding is operably coupled to an antenna.

Claims

1. A radio frequency (RF) antenna coupling structure comprises:

a first transformer having a primary winding and a secondary winding, wherein the primary winding of the first transformer is operably coupled to a power amplifier, and wherein the secondary winding of the first transformer has a desired output impedance;

a second transformer having a primary winding and a secondary winding, wherein the primary winding of the second transformer is operably coupled to a low noise amplifier, and wherein the secondary winding of the second transformer has a desired output impedance; and

a transformer balun having a differential winding and a single-ended winding, wherein the differential winding is operably coupled to the secondary windings of the first and second transformers and the single-ended winding is operably coupled to an antenna.

2. The RF antenna coupling structure of claim 1 further comprises:

the primary winding of the first transformer having a first impedance; and

the primary winding of the second transformer having a second impedance, wherein the second impedance is much greater than the first impedance such that the first transformer provides a low drive impedance to substantially match output impedance of the power amplifier and the second transformer provides a high load impedance to substantially match input impedance of the low noise amplifier.

3. The RF antenna coupling structure of claim 1 further comprises:

a first transistor coupled to one node of the single-ended winding;

a second transistor coupled to another node of the single-ended winding, wherein the antenna is coupled to the another node of the single-ended winding, a second antenna is coupled to the one node of the single-ended winding, wherein, when the first transistor is active, the antenna is actively coupled to the single-ended winding and when the second transistor is active, the second antenna is actively coupled to the single-ended winding.

4. The RF antenna coupling structure of claim 1 wherein tie transformer balun further comprises a turns ratio of one-to-one.

5. The RF antenna coupling structure of claim 1 further comprises:

the first transformer, the second transformer, and the transformer balun being fabricated on a radio frequency integrated circuit.

6. A radio frequency integrated circuit comprises:

transmitter section that includes a transmit filter module, a transmit mixing module, and a power amplifier interoperably coupled to convert outbound low intermediate frequency (IF) signals into outbound radio frequency (RF) signals;

receiver section that includes a low noise amplifier, a receive mixing module, and a receiver filter module interoperably coupled to convert inbound RF signals into inbound low IF signals; and

an antenna coupling structure that includes;

a first transformer having a primary winding and a secondary winding, wherein the primary winding of the first transformer is operably coupled to the power amplifier, and wherein the secondary winding of the first transformer has a desired output impedance;

a second transformer having a primary winding and a secondary winding, wherein the primary winding of the second transformer is operably coupled to the low noise amplifier, and wherein the secondary winding of the second transformer has a desired output impedance; and

a transformer balun having a differential winding and a single-ended winding, wherein the differential winding is operably coupled to the secondary windings of the first and second transformers and the single-ended winding is operably coupled to an antenna.

7. The radio frequency integrated circuit of claim 6 further comprises:

the primary winding of the first transformer having a first impedance; and

the primary winding of the second transformer having a second impedance, wherein the second impedance is much greater than the first impedance such that the first transformer provides a low drive impedance to substantially match output impedance of the power amplifier and the second transformer provides a high load impedance to substantially match input impedance of the low noise amplifier.

8. The radio frequency integrated circuit of claim 6 further comprises:

a first transistor coupled to one node of the single-ended winding;

a second transistor coupled to another node of the single-ended winding, wherein the antenna is coupled to the another node of the single-ended winding, a second antenna is coupled to the one node of the single-ended winding, wherein, when the first transistor is active, the antenna is actively coupled to the single-ended winding and when the second transistor is active, the second antenna is actively coupled to the single-ended winding.

9. The radio frequency integrated circuit of claim 6, wherein the transformer balun further comprises a turns ratio of one-to-one.