Design and Test of an L-Band (GNSS) Low Noise Amplifier and Limiter

Abstract

Abstract
This thesis work was performed at RUAG Space AB, Göteborg, Sweden. The aim of this thesis is to test the performance boundaries of SiGe based heterojunction bipolar transistor in designing a low noise amplifier meant for GNSS applications.
After careful consideration of different alternatives for active components in SiGe HBT process, BFY640-04 from Infineon was selected as the active component for the design. Later, different topologies have been evaluated in Advanced Design System (ADS) software and finally a common emitter topology is selected considering cost-effectiveness, performance and simplicity. Apart from this, the functionality of a limiter component namely, GG-77015-01 from Microsemi has been tested by placing it in front of the LNA. The purpose of this is to know if it can prevent the LNA from high power levels and to study its overall effect on noise figure, gain and linearity. The prototypes were fabricated on a hardback PCB consisting of Roger Duroid 6002 substrate.
The designed LNA has less than 1 dB (excluding limiter) noise figure, gain of 17-13 dB and input return loss of 6 dB. It is powered by a single positive supply of +5 V and has very low DC power consumption of 15 mW. Also, the noise figure is fairly low in the entire L-band apart from current GNSS bands, which provides possibility of this design to be useful in future GNSS applications too.

Popular Abstract

Low power, highly stable and wideband low noise amplifier in Silicon Germanium technology
A radio frequency amplifier is intended to amplify incoming weak signals coming from antenna without adding too much noise to signal, hence its termed as “Low noise amplifier”. High gain, high linearity, low noise, low power consumption are its important requirements. Imagine such a device which introduces very low noise, bears low power and is usable in a wide range of frequencies. And, of course, its cost-effective as well. Wow! . This design promises exactly these characteristics.
Currently, most of the radio frequency (RF) front ends are designed for 1575.42 MHz since it is the GPS L1 band which is the most important band for navigation purposes. With the incoming of new satellite navigation systems like Galileo which transmits signals at E1 (centered at 1575.42 MHz), E5a (centered at 1176.45 MHz) , E5b(centered at 1207.140 MHz) and E6 (centered at 1278.75MHz) there is a need for more versatile RF front ends which have a wider reception range. The implemented design is intended to work in almost the entire L-band (1-2 GHz). Thus, it provides the flexibility to be useful in current and future Global Navigation Satellite Systems (GNSS). It has a noise figure of less than 1 decibel. The power consumption is as low as 15 milliwatts. The design is very simple and cost-effective. This is obtained by use of extremely simple yet effective DC biasing circuits, and minimum number of components to match input and output. A matching circuit at the input side provides low noise in the design. A silicon germanium heterojunction bipolar transistor is used as the active component in the design. It uses a single supply voltage which makes the design more beneficial. The ability of the design to sustain high input power levels is a surprise component. Yes, the design has been improvised to prevent it from destruction by high input power levels. This is done by incorporating a limiter component in front of the design. This adds very low noise (≤ 0.25 decibel) and is usable in the designed frequency range.

• author: Navneeta, Ms
• supervisor: Johan Wernehag
• organization: Department of Electrical and Information Technology
• course: EITM02 20151
• year: 2015
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• report number: LU/LTH-EIT 2015-459
• language: English
• id: 7854757
• date added to LUP: 2015-09-04 09:21:22
• date last changed: 2015-09-04 09:21:22