Wide band electrical balance duplexer with balanced bridge circuit

1. A circuit for a wideband electrical balance duplexer (EBD), the circuit comprising:

a first impedance element coupled between a first and a second node of a bridge circuit;

a second impedance element coupled between the second and a third node of the bridge circuit;

an antenna configured to receive and transmit RF signals, the antenna being coupled between the first and a fourth node of the bridge circuit; and

a balancing network configured to provide an impedance that substantially matches an impedance of the antenna, the balancing network being coupled between the third and the fourth node of the bridge circuit, wherein

a) at least one of the first or the second impedance elements are configured to facilitate balancing the bridge circuit,

b) one or more output nodes of a transmit (TX) path are coupled to an input node of the bridge circuit, and

c) one or more input nodes of a receive (RX) path are coupled between the second and the fourth node of the bridge circuit.

2. The circuit of claim 1 , wherein:

a) balancing the bridge circuit comprises providing substantially identical signals at the second and the fourth node of the bridge circuit,

b) the identical signals comprise at least one of a voltage or a current signal,

c) the input nodes of the RX path comprises one or more input nodes of at least one low noise amplifier (LNA) of an RF transceiver, and

d) the LNA comprises a differential LNA.

3. The circuit of claim 2 , wherein the LNA is a single-ended LNA that is coupled to the balanced bridge circuit via a transformer.

4. The circuit of claim 1 , wherein:

a) the one or more output nodes of the TX path comprise one or more output nodes of at least one power amplifier (PA) of an RF transceiver,

b) the input node of the bridge circuit comprises the first node, and

c) the third node of the bridge circuit is coupled to ground potential.

5. The circuit of claim 4 , wherein the antenna is coupled to the bridge circuit using a transformer.

6. The circuit of claim 1 , wherein

a) the input node of the bridge circuit comprises the third node, and

b) the first node of the bridge circuit is coupled to ground potential.

7. The circuit of claim 6 , wherein the antenna is configured to provide a voltage signal between the first node and the fourth node of the bridge circuit.

8. The circuit of claim 1 , wherein the bridge circuit is configured to isolate the one or more output nodes of the TX path from the one or more input nodes of the RX path, and wherein the bridge circuit is configured to substantially reduce a noise signal generated by an impedance associated with the antenna at the one or more input nodes of the RX path.

9. The circuit of claim 1 , wherein:

a) the balancing network comprises a plurality of passive elements, each selectable via a switch,

b) the plurality of passive elements comprise capacitors and resistors, and

c) the switch comprises a MOS switch.

10. A method of providing a wideband electrical balance duplexer (EBD), the method comprising:

coupling a first impedance element between a first and a second node of a bridge circuit;

coupling a second impedance element between the second and a third node of the bridge circuit;

coupling an antenna between the first and a fourth node of the bridge circuit, the antenna being configured to transmit and receive RF signals; and

coupling a balancing network between the third and the fourth node of the bridge circuit, the balancing network being configured to provide an impedance that substantially matches an impedance of the antenna, wherein

a) at least one of the first or the second impedance elements are configured to facilitate balancing the bridge circuit,

b) one or more output nodes of a transmit (TX) path are coupled to an input node of the bridge circuit, and

c) one or more input nodes of a receive (RX) path are coupled between the second and the fourth node of the bridge circuit.

11. The method of claim 10 , wherein:

a) balancing the bridge circuit comprises providing substantially identical signals at the second and the fourth node of the bridge circuit,

b) the identical signals comprise at least one of a voltage or a current signal,

c) the input nodes of the RX path comprises one or more input nodes of at least one low noise amplifier (LNA) of an RF transceiver, and

d) the LNA comprises a differential LNA.

12. The method of claim 11 , wherein the LNA is a single-ended LNA that is coupled to the balanced bridge circuit via a transformer.

13. The method of claim 10 , wherein:

a) the one or more output nodes of the TX path comprise one or more output nodes of at least one power amplifier (PA) of the an RF transceiver,

b) the input node of the bridge circuit comprises the first node, and

c) the third node of the bridge circuit is coupled to ground potential.

14. The method of claim 13 , wherein coupling the antenna between the first and the fourth node of the bridge circuit comprises coupling the antenna to the bridge circuit by using a transformer.

15. The method of claim 10 , wherein

a) the input node of the bridge circuit comprises the third node, and

b) the first node of the bridge circuit is coupled to ground potential.

16. The method of claim 15 , wherein the antenna is configured to provide a voltage signal between the first node and the fourth node of the bridge circuit.

17. The method of claim 10 , further comprising configuring the bridge circuit to isolate the one or more output nodes of the TX path from the one or more input nodes of the RX path, and wherein the bridge circuit is configured to substantially reduce a noise signal generated by an impedance associated with the antenna at the one or more input nodes of the RX path.

18. The method of claim 10 , wherein:

a) coupling the balancing network between the third and the fourth node of the bridge circuit comprises coupling a plurality of passive elements between the third and the fourth node of the bridge circuit, each passive element being selectable via a switch,

b) the plurality of passive elements comprise capacitors and resistors, and

c) the switch comprises a MOS switch.

19. A transceiver, comprising:

an antenna configured to transmit and receive RF signals; and

a wideband electrical balance duplexer (EBD) circuit configured to isolate one or more output nodes of a TX path of the transceiver from one or more input nodes of an RX path of the transceiver, the wideband electrical balance duplexer comprising:

a first impedance element coupled between a first and a second node of a bridge circuit;

a second impedance element coupled between the second and a third node of the bridge circuit; and

a balancing network configured to provide an impedance that substantially matches an impedance of the antenna, the balancing network being coupled between the third and a fourth node of the bridge circuit, wherein

a) the antenna is coupled between the first and the fourth node of the bridge circuit,

b) at least one of the first or the second impedance elements are configured to facilitate balancing the bridge circuit,

c) one or more output nodes of the TX path is coupled to an input node of the bridge circuit, and

d) one or more input nodes of the RX path are coupled between the second and the fourth node of the bridge circuit.

20. The transceiver of claim 19 , wherein,

a) balancing the bridge circuit comprises providing substantially identical signals at the second and the fourth node of the bridge circuit,

b) the identical signals comprise at least one of a voltage or a current signal,

c) the input nodes of the RX path comprises one or more input nodes of at least one low noise amplifier (LNA), including a differential LNA,

d) the one or more output nodes of the TX path comprise one or more output nodes of at least one power amplifier (PA), and

e) the bridge circuit is configured to substantially reduce a noise signal generated by an impedance associated with the antenna at the one or more input nodes of the RX path.