A wideband (0.8–6 GHz) receiver front-end (RFE) utilizing a shunt resistive feedback low-noise amplifier (LNA) and a micromixer is realized in 90 nm CMOS technology for software-defined radio (SDR) applications. With the shunt resistive feedback and series inductive peaking, the proposed LNA is able to achieve a wideband frequency response in input matching, power gain and noise figure (NF). A micromixer down converts the radio signal and performs single-to-differential transition. Measurements show the conversion gain higher than 17 dB and input matching (S11) better than −7.3 dB from 0.8 to 6 GHz. The IIP3 ranges from −7 to −10 dBm, and the NF from 4.5 to 5.9 dB. This wideband receiver occupies 0.48 mm2 and consumes 13 mW.
Software-defined radio was designed to process any signal within a certain bandwidth [
The intuitive SDR receiver topology is to connect front-ends of different standards in parallel as shown in Figure
(a) Multiband receiver architecture. (b) Wideband or tunable-band receiver architecture.
A wideband RFE can be implemented by several circuit structures. Conventional common-gate LNAs feature wide input matching and gain bandwidths [
In order to solve the above issues, a wideband RFE utilizing a resistive feedback LNA and a micromixer is proposed. This LNA adopts the resistive feedback technique and inductive peaking to extend the bandwidth [
Figure
Block diagram of SDR receiver.
Figure
Schematic of proposed receiver front-end.
The small-signal model of the proposed LNA is shown in Figure
Small-signal model of wideband LNA.
The voltage gain of the LNA,
The noise figure of the LNA is derived according to [
Note that
Apart from bandwidth extension, the resistive feedback topology improves the linearity of the amplifier [
A micromixer possesses wideband input matching, high linearity, and single-to-differential conversion ability, which makes this topology suitable for the proposed SDR application.
Single-to-differential conversion is accomplished by injecting the signal current into the source of transistor
The conversion gain of the micromixer can be derived as (
The conversion gain of the RFE can be expressed by the product of (
The RFE was realized in 1P9M 90 nm CMOS technology. On-wafer measurement was performed by using an Agilent 8722ES network analyzer for input matching measurements. Signal generators Agilent E8257D and Agilent E4438C are used to provide LO and RF signals, respectively. Spectrum analyzer Agilent E4440A is used for IF spectrum and noise figure measurements.
Figure
Input matching of the proposed receiver front-end.
Conversion gain of the proposed receiver front-end.
Noise figure of the proposed receiver front-end.
The input third intercept points (IIP3) are in the range from −10 to −7 dBm over the frequency of interest as shown in Figure
Summary of the implemented and recently reported state-of-the-art CMOS wideband and tunable-band receiver front-ends.
Frequency (GHz) |
|
Conversion gain (dB) | Noise figure (dB) | IIP3 (dBm) | Supply voltage (V) | Power (mW) | Area (mm2) | Technology | |
---|---|---|---|---|---|---|---|---|---|
This work | 0.8~6 | <−7.3 | 17~20* | 4.5~5.9 | −10~−5 | 1 | 13* | 0.48* | 90 nm CMOS |
[ |
0.6~10 | <−10 | 14* | 7 | 0 | 1.2 | 30* | 1* | 45 nm CMOS |
[ |
2~8 | −8 | 23* | 4.5 | −7 | 1.2 | 27.8* | 0.48* | 65 nm CMOS |
[ |
0.8~6 | N/A | 18~20# | 5~5.5 | −3.5 | 2.5 | 28.5* | 3.8$ | 90 nm CMOS |
[ |
0.6~3 | <−8 | 42~48$ | 3 | −14 | 1.2 | 30$ | 1.5$ | 130 nm CMOS |
[ |
0.1~3 | N/A | 33~55$ | 3.5~6 | N/A | 1.2 | 14.5~48.5$ | 2.2$ | 130 nm CMOS |
[ |
0.1~5 | N/A | −2~82$ | 2.3~6.5 | −10~−3 | 1.1 | 59~115$ | 2$ | 45 nm CMOS |
[ |
3~5 | <−7.6 | 19.8~24.6* | 15.4~17.4 | >−6 | 2 | 16* | 1.14* | 0.18 um CMOS |
[ |
3~8 | N/A | 15~21* | 5~6.5 | −2.6 | 2.3 | 44.9* | 0.35*@ | 0.18 um CMOS |
IIP3 of the proposed receiver front-end.
The chip area is 0.48 mm2 including testing pads as shown in Figure
Chip micrograph.
A wideband RFE from 0.8 to 6 GHz is proposed by using a resistive feedback amplifier and a micromixer. The measurement results show a flat and wideband feature in input matching, gain, and noise performance. The proposed RFE features the lowest power consumption (13 mW) among recently reported silicon-based RFEs in 0.8 – 6 GHz range.
The authors are very grateful to United Microelectronics Corporation (UMC), Hsin-Chu, Taiwan, for chip fabrication, and National Nano-Device Laboratory (NDL), Hsin-Chu, Taiwan, for their technical supports. This work was supported by the National Science Council under Grant NSC-98-2221-E-002-155-MY2.