Front-end system for radio devices

• US 8,971,831 B2
• Filed: 02/15/2013
• Issued: 03/03/2015
• Est. Priority Date: 02/17/2012
• Status: Active Grant

• Current Assignee: IMEC International
• Original Assignee: IMEC International
• Inventors: Vidojkovic, Vojkan, Vaesen, Kristof, Wambacq, Piet
• Primary Examiner(s): Nguyen, Duc M
• Application Number:
  US13/768,148
• Publication Number:
  US 20130214863A1
• Time in Patent Office: 746 Days
• Field of Search: 455/326, 455/232.1, 455/245.1, 455/280
• US Class Current: 455/232.1
• CPC Class Codes: H03F 2200/141 the feedback circuit of the amplifier stage comprising a resistor and a capacitor in series, at least one of them being an active one
• CPC Class Codes: H03F 2200/144 the feedback circuit of the amplifier stage comprising a passive resistor and passive capacitor
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/534 Transformer coupled at the input of an amplifier
• CPC Class Codes: H03F 2200/537 A transformer being used as coupling element between two amplifying stages
• CPC Class Codes: H03F 2200/541 Transformer coupled at the output of an amplifier
• CPC Class Codes: H03F 3/45071 with semiconductor devices only
• 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
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22

Abstract

The present disclosure relates to a front-end system for a radio device, the front-end system comprising a low-noise amplifier (LNA), arranged for receiving a radio frequency input signal (RF_IN) and arranged for outputting an amplified radio frequency signal (RF_OUT), wherein the low-noise amplifier comprises a first differential amplifier, and a mixer (MIX), arranged for down-converting the amplified radio signal (RF_OUT) provided by the low-noise amplifier (LNA) to a baseband signal (BB), by multiplying the amplified radio signal (RF_OUT) with a local oscillator (LO) frequency tone, said low-noise amplifier (LNA) and said mixer (MIX) being inductively coupled.

Claims

1. A front-end system for a radio device comprising:

a low-noise amplifier arranged for receiving an input signal and for outputting an amplified signal and comprising a first amplification stage and a second amplification stage, wherein the first amplification stage comprises a resistive shunt feedback circuit that includes a capacitor in series with a resistor, the capacitor providing DC decoupling of the low-noise amplifier; and

a mixer arranged for down-converting the amplified signal provided by the low-noise amplifier to a baseband signal by multiplying the amplified signal with a local oscillator frequency tone, wherein the low-noise amplifier and the mixer are transformer-coupled.

2. The front-end system of claim 1, wherein the low-noise amplifier includes a neutralization circuit comprising a cross-coupled capacitor.

3. The front-end system of claim 1, wherein the second amplification stage is inductively coupled to the first amplification stage.

4. The front-end system of claim 1, wherein the low-noise amplifier is inductively coupled to an antenna.

5. The front-end system of claim 1, further comprising, at an input of the low-noise amplifier, an input transformer with a turn ratio of about 1:

3 and coupling factor of about 0.5.

6. The front-end system of claim 1, wherein the mixer is a passive voltage switching mixer.

7. The front-end system of claim 1, wherein the mixer is implemented differentially.

8. A radio device comprising a front-end system, wherein the front end system includes:

a low-noise amplifier arranged for receiving an input signal and for outputting an amplified signal and comprising a first amplification stage and a second amplification stage, wherein the first amplification stage comprises a resistive shunt feedback circuit that includes a capacitor in series with a resistor, the capacitor providing DC decoupling of the low-noise amplifier; and

a mixer arranged for down-converting the amplified signal provided by the low-noise amplifier to a baseband signal by multiplying the amplified signal with a local oscillator frequency tone, wherein the low-noise amplifier and the mixer are transformer-coupled.

9. The radio device of claim 8, wherein the low-noise amplifier includes a neutralization circuit comprising a cross-coupled capacitor.

10. The radio device of claim 8, wherein the second amplification stage is inductively coupled to the first amplification stage.

11. The radio device of claim 8, wherein the low-noise amplifier is inductively coupled to an antenna.

12. The radio device of claim 8, further comprising, at an input of the low-noise amplifier, an input transformer with a turn ratio of about 1:

3 and coupling factor of about 0.5.

13. The radio device of claim 8, wherein the mixer is a passive voltage switching mixer.

14. The radio device of claim 8, wherein the mixer is implemented differentially.

15. A differential low-noise amplifier comprising:

a first amplification stage and a second amplification stage,

wherein the first amplification stage comprises a resistive shunt feedback circuit that includes a capacitor in series with a resistor, the capacitor providing DC decoupling of the differential low-noise amplifier,

wherein the first amplification stage further comprises a neutralization circuit that includes a cross-coupled capacitor, and

wherein the differential low-noise amplifier is adapted for use in a front-end system of a radio device.

16. The differential low-noise amplifier of claim 15, wherein the first amplification stage is inductively coupled to the second amplification stage.

17. The differential low-noise amplifier of claim 15, wherein the differential low-noise amplifier is configured to inductively receive an input signal from an antenna.

18. The differential low-noise amplifier of claim 15, further comprising an input transformer with a turn ratio of about 1:

3 and a coupling factor of about 0.5.