Tunable RF filter based RF communications system

• US 9,866,197 B2
• Filed: 06/06/2014
• Issued: 01/09/2018
• Est. Priority Date: 06/06/2013
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Inventors: Maxim, George, Leipold, Dirk Robert Walter, Scott, Baker
• Primary Examiner(s): Patel, Rakesh
• Application Number:
  US14/298,863
• Publication Number:
  US 20140361849A1
• Time in Patent Office: 1,313 Days
• Field of Search: 333132, 333174, 333175
• CPC Class Codes: H01L 23/4824 Pads with extended contours, e.g. grid structure, branch structure, finger structure
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/111 the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not
• CPC Class Codes: H03F 2200/267 A capacitor based passive circuit, e.g. filter, being used in an amplifying circuit
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2203/7209 the gated amplifier being switched from a first band to a second band
• CPC Class Codes: H03F 3/193 with field-effect devices H03F3/195 takes precedence
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/68 Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics power amplifiers using a combination of several semiconductor amplifiers H03F3/211; combinations of amplifiers using coupling networks with distributed constants H03F3/602
• CPC Class Codes: H03F 3/72 Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal
• CPC Class Codes: H03H 2210/012 Centre frequency; Cut-off frequency
• CPC Class Codes: H03H 2210/025 Capacitor
• CPC Class Codes: H03H 2210/04 Filter calibration method
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence
• CPC Class Codes: H03H 7/0153 Electrical filters; Controlling thereof
• CPC Class Codes: H03H 7/09 Filters comprising mutual inductance
• CPC Class Codes: H03H 7/1775 Parallel LC in shunt or branch path H03H7/1791 takes precedence
• CPC Class Codes: H03H 7/46 Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source for use in multiplex transmission systems H04J1/00
• CPC Class Codes: H03H 7/463 Duplexers
• CPC Class Codes: H03H 7/465 having variable circuit topology, e.g. including switches
• CPC Class Codes: H04B 1/1027 : assessing signal quality or detecting noise/interference for the received signal
• 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

RF communications circuitry, which includes a first RF filter structure, is disclosed. The first RF filter structure includes a first tunable RF filter path and a second tunable RF filter path. The first tunable RF filter path includes a pair of weakly coupled resonators. Additionally, a first filter parameter of the first tunable RF filter path is tuned based on a first filter control signal. A first filter parameter of the second tunable RF filter path is tuned based on a second filter control signal.

Claims

1. An apparatus having a first common connection node and comprising:

radio frequency (RF) receive circuitry;

RF transmit circuitry;

a first tunable RF filter path comprising a pair of weakly coupled resonators and directly connected between the first common connection node and the RF receive circuitry, wherein an energy transfer factor between each of the pair of weakly coupled resonators is less than ten percent, the first tunable RF filter path is configured to receive and filter a first RF receive signal via the first common connection node to provide a first filtered RF receive signal to the RF receive circuitry, a first filter parameter of the first tunable RF filter path is configured to be tuned based on a first filter control signal, and the first tunable RF filter path is further configured to function as an RF lowpass filter, such that the first filter parameter of the first tunable RF filter path is a break frequency of the RF lowpass filter; and

a second tunable RF filter path directly connected between the first common connection node and the RF transmit circuitry, wherein the second tunable RF filter path is configured to receive and filter a first RF transmit signal from the RF transmit circuitry to provide a first filtered RF transmit signal via the first common connection node, such that the apparatus is configured to be used as a TDD (Time Division Duplex) communications system, the first RF receive signal and the first filtered RF transmit signal are half-duplex signals, a first filter parameter of the second tunable RF filter path is configured to be tuned based on a second filter control signal, and the second tunable RF filter path is further configured to function as an RF highpass filter, such that the first filter parameter of the second tunable RF filter path is a break frequency of the RF highpass filter.

2. The apparatus of claim 1 wherein the first common connection node is coupled to a first RF antenna.

3. The apparatus of claim 2 wherein the first filtered RF transmit signal is configured to be transmitted via the first common connection node by the first RF antenna.

4. The apparatus of claim 2 wherein the first RF antenna is configured to forward a received RF signal via the first common connection node to provide the first RF receive signal.

5. The apparatus of claim 1 wherein the first common connection node is directly connected to a first RF antenna.

6. The apparatus of claim 1 further comprising a first RF filter structure, which comprises the first tunable RF filter path and the second tunable RF filter path.

7. The apparatus of claim 1 wherein:

a second filter parameter of the first tunable RF filter path is configured to be tuned based on the first filter control signal; and

a second filter parameter of the second tunable RF filter path is configured to be tuned based on the second filter control signal.

8. The apparatus of claim 7 wherein:

the first tunable RF filter path is further configured to function as a first RF bandpass filter;

the second filter parameter of the first tunable RF filter path is a center frequency of the first RF bandpass filter;

the second tunable RF filter path is further configured to function as a second RF bandpass filter; and

the second filter parameter of the second tunable RF filter path is a center frequency of the second RF bandpass filter.

9. The apparatus of claim 1 wherein control circuitry is configured to provide the first filter control signal and the second filter control signal.