Low Noise Amplifier Selection for Indian Regional Navigation Satellite System

Transcription

1 Low Noise Amplifier Selection for Indian Regional Navigation Satellite System Gayathri K. M. and Dr. Thangadurai N. Department of Electronics and Communication Engineering, School of Engineering and Technology, Jain University, Bangalore, Karnataka, India. Abstract indigenous and autonomous satellite navigation system being developed by Indian Space Research Organization. IRNSS operates in two frequency bands namely L band ( MHz) and S band ( MHz). In this IRNSS receiver the Low Noise Amplifier (LNA) plays a very important role in the RF front end. The design of LNA is very critical in satellite communication system. This paper presents a design selection of LNA for the two frequency bands used for IRNSS. The design should be stable with a gain of 32dB and a noise figure of 0.9dB over a bandwidth of 25 MHz and with low power consumption. Keywords: Satellite Navigation System, Noise Figure, Gain, Power Consumption Introduction Indian Regional Navigation Satellite System (IRNSS) satellite based navigation system being developed by Indian Space Research Organization. It is developed to provide position information to users in Indian region extending up to 1500 km from its boundary [1]. In September 2014, signal in space interface control document was released, which contains the information of its system architecture, frequency spectrum, satellite constellation, signal spectrum, satellite constellation, signal structure, modulation scheme and information of the navigation payload. IRNSS consists of 3 segments namely: Space segment, Ground segment and User segment. The Space segment consists of seven satellites, 4 in geostationary orbit (GEO) which are positioned over 34, 83 and 132 East respectively and 3 in inclined geosynchronous (IGSO) orbit which are positioned over longitudes of 55º E and º E respectively. Figure 1: Frequency Spectrum of Various Navigational Systems Six of the seven satellites are already in space. Figure 1 shows the frequency spectrum of IRNSS compared with existing navigational systems like GPS, GLONASS and GALILEO. IRNSS Receiver The Ground segment consists of the IRNSS Ranging and Integrity Monitoring stations (IRIM) and Navigation control centre (INC). IRIM receives the data from the space and transmits to navigation control centre. INC controls the IRNSS system and also maintains the accurate time reference with IRNSS network timing centre. Using CDMA ranging and laser ranging, the position of the satellite and orbit maintenance in space are monitored. The navigation uplink centres which are part of Spacecraft Control Facility (SCF) update the navigation data using Telemetry, Tracking and Command (TT&C) system. The block diagram of the IRNSS User receiver is shown in the Figure 2. Figure 2: IRNSS User Receiver The user segment consists of IRNSS receiver which operates in, single frequency (L5 or S band) or dual frequency (L5 and S band). It offers two services to the users: i) Standard Positioning Service (SPS) which is free of cost to the users and uses unencrypted data; ii) Restricted Service (RS) which uses encrypted data for authorised users. The SPS signal uses Code Division Multiple Access (CDMA) modulation with Binary Phase Shift Keying (BPSK). The navigation data rate is 50 Hz and Pseudo-Random Noise (PRN) code rate is MHz with duration 1ms. The navigation data is modulo-2 added with the PRN code sequence followed by modulation with the Radio Frequency (RF) carrier at the L5 frequency. Some applications of IRNSS are: Terrestrial, Aerial and marine navigation, disaster management, vehicle tracking and fleet management, integration with mobile phones, precise timing, mapping and geodetic data capture, Terrestrial navigation aid for hikers and travellers, visual and voice navigation for drivers. Low Noise Amplifier (LNA) In radio wave propagation the loss is very high, so the signals 5352

2 travelling from the transmitter normally suffer from degradation. When these signals are received at the receiving antenna, they are very weak. Low Noise Amplifier (LNA), which is the combination of the low-noise, high-gain, and stability over the entire range of operating frequency and is placed very close to the antenna, is crucial RF component employed in receiver systems in order to amplify these very weak RF signals captured by the antenna, and also to boost desired signal power while adding as little noise and distortion as possible so that the noise added by later components of the RF receiver chain has less effect on the Signal-to-Noise Ratio (SNR), and the overall performance [5] [8] [10]. Figure 3: Basic Low Noise Amplifier Circuit The basic low noise amplifier circuit diagram is shown in the Figure 3. LNA is a basic building block in RF communication systems. It is important part of the receiver and placed at the front of the receiver, which amplifies the very low signal without degrading its SNR. The low noise amplifier can perform multiple operations such as weak signal amplification, reduction of noise, increased gain, high stability, reduce noise figure and eliminate channel interference. A good LNA has a low NF (like 1dB), a large enough gain (like 32dB) and should have large enough inter modulation and compression point (IP3 and P1dB). Due to the development of navigation system such as IRNSS, GPS, etc the demand for LNA also increased. The LNA should have a high sensitivity and be able to amplify the received signals with a very low level of amplitude without increasing the noise level. The LNA determines the signal to noise ratio of the whole receiver band. In order to increase the performance and accuracy of the system the LNA should have low Noise Figure (NF) and high linearity [9]. Types of Low Noise Amplifier Wide Band LNA Wideband LNA is used to provide the high data rate transmission with wide range of frequency. Wide band LNA will give maximum gain over relatively narrow bandwidth, but difficult to match the input and output of the amplifier. A wide-band LNA design must not only match the source impedance over a wide range of frequencies, but also able provide low NF, flat gain and high linearity at the same time. The rapid increasing popularity of wide band (0.3 3 GHz) and ultra wide band ( GHz) applications has augmented the demand for manufacturing low cost but high performance low noise amplifiers. Wide band Low Noise Amplifier is vital component in many high data rate and wide band applications including Optical sensors, Pulsed RADARs, Satellites systems, Analog cable systems, Terrestrial television broadcasting networks, Cellular communication base stations and Software defined Radios etc. The major advantage of wide band Low noise amplifier over narrow band is that the former can replace several narrow band LC tuned low noise amplifiers in multi standard narrow band receivers. This results in drastic reduction in manufacturing cost and circuit complexity. Wide band utilization also reduces the chip area and number of input and output pins if it is implemented in chip fabrication. Wireless wideband communication systems in Gbits/sec data rate, either regulated or not by the international standards, are going to be the centre of research and development in future [12] [7]. Dual Band LNA For the multi-band LNA design, the main considerations include simple and feasible off-chip input matching, noise figure level control, power dissipation constraint, and voltage gain on different bands. Therefore, the tradeoffs among interdependent parameters, the iteration on analysis and the multi-band consideration have increased the difficulties of the design. The design challenges of a dual-band LNA includes dual-band input/output matching, low noise and low power consumption. Several approaches have emerged as dominant techniques proposed for the design of dual-band LNA. The conventional dualband architectures adopt two single-band LNAs in parallel, which provides high performance at all frequency bands. The disadvantages are it requires a large chip area and a mixer with a complex input circuit, but also dissipates more power. Other topology adopts a wide-band circuit to amplify all signals in the whole frequency band. But this includes the interference signal from the outside working band and also generates input and output mismatch in the wideband range. A dualband LNA constructed by one signal path has advantages of lower cost and low power consumption compared with other topologies [13] [6]. LNA Parameters Bandwidth: Bandwidth is defined as the difference between the high frequency and low frequencies of the operating range. BW= f H -f L Hz (1) Noise-Figure: It is the ratio of output SNR to the input SNR in db: db (2) 1 db compression point: The linearity at a LNA is expressed by the 1 db compression point. When the input signal is increased, a point is reached where the power of the signal is 5353

3 not amplified by the same amount as the smaller signal at the output. At this point where the input signal is amplified by an amount 1 db less than the small signal gain, this point is called 1 db compression point. IIP3: Input Inter-Modulation (IIP3) product is proportional to the ratio of the first and third derivatives of the transfer characteristic. IIP3 is expressed as: Design Specifications The various specifications for the design of a low noise amplifier are listed below: a) Noise figure: less than 1 db was desired. b) Stability: Highly stable amplifier was most important. c) Gain: Single stage transistor with better gain. d) Input return loss: Balanced design e) Output return loss: Inter-stage matching would be used in multi-stage LNA and there was no requirement on output return loss. f) Limiter component: In order to make the LNA capable of working under high input power conditions, a limiter component is needed. Existing LNAs Sarang Thombre et. al., has designed and implemented a Low Noise Amplifier which operates over a wide range of frequencies of 1164MHz to MHz. This LNA is designed for overlapping frequency bands of all the three GNSS constellations, namely American GPS, European Galileo and Russian GLONASS system. The LNA has been designed for a Gain of 18dB and noise figure of 2dB for a bandwidth of 450MHz. The author could able to achieve high degree of linearity with output of 1dB compression at +13dB and output third order intercept at +23dB. The author has designed an LNA with a centre frequency of MHz and achieved a gain of 18.5dB with noise figure 2.18dB and current consumption of 18.6mA. The design has been simulated using Agilent ADS simulation software [2]. Navneeta Deo et. al., has designed a SiGe based Low Noise Amplifier for entire L-band frequencies. The author could able to achieve a noise figure of db and gain of db in a frequency of L-band. They proved that for GNSS application, which requires a low noise figure, can be achieved by using BFY transistor. They have used a HBT process for the design and compared also with phemt and MESFET process. They have implemented different topologies of LNA. The design has been simulated using Agilent ADS simulation software [3] [11]. Md. Maruf Hossain et. al., has designed and implemented a RF front end which consists of LNA and filters. The LNA has been designed for a frequency range of 1.1 to 1.7 GHz with a noise figure of 1.01 db and gain of db. The author could able to achieve 1 db compression at db and output third order intercept at db. They have implemented LNA on Rogers RO4003 substrate and Murata capacitors, Coil craft inductors and Neohm resistors. For the (3) measurement of the LNA parameters the author has used ADS software. Most at the LNA designs available in our survey are only at design level. There is no greater sign at fabrication and testing of those LNA s for navigation system especially for IRNSS [4]. LNA for IRNSS The low noise amplifier is a special type of electronic amplifier used in IRNSS receiver to catch up and amplify very weak signals from the noisy channel captured by an antenna. It is located very next to the antenna before other receiver components. That is why the first stages of a receiver have a great impact on the overall NF. The well known Frii s formula is the best understanding of the importance of LNA as given in equation 4, because the overall noise figure of the receiver front-end is dominated by the first stage. (4) LNA is one of the topics of research due to the different performance requirements for different standards. Gain, NF, linearity, and low power consumption are the major specifications in the design of LNA, and the most important parameter is NF. Figure 4: Noise Figure Vs Frequency of LNA The proposed methodology is used to design and implement a LNA for IRNSS receiver. The design specification for the proposed design is given in the table 1. Figure 4 and 5 shows the performance noise figure and gain with respect to the frequency. 5354

4 Figure 5: Gain Vs Frequency of LNA Equation 5 to 8 shows the relationship between the noise figure and the gain. (5) (6) (7) Table 1: Design specification of chosen LNA (8) Parameters Frequency Gain Noise figure P1dB QIP3 Power consumption Operating Temperature Design Specification MHz and MHz 32dB 0.9dB <13.5dBm <23.5dBm <55mW -30 o C to +60 o C Figure 6 shows the process flow diagram involved in proposed LNA design fabrication and testing. Once the design specifications validated by simulation will go for fabrication and testing. Figure 6: Process Flow of Design and Implementation Conclusion satellite based navigation system being developed by Indian Space Research Organization. In IRNSS receiver, the LNA is a basic building block. The LNA proposed here meant for two bands of IRNSS with a gain of 32dB and noise figure of 0.9dB. So the wide band or dual band LNA should be opted for design to adapt both L5 and S band signals. The design of this LNA is to be verified with final delivered metrics. The same will be fabricated and tested in the future and can be implemented with real time IRNSS Receiver. Acknowledgement The authors hereby acknowledge ISRO-SAC, Ahemdabad and Jain University, Bangalore for the successful completion of this work. Also acknowledges Dr. G. Raju, Professor, Jain 5355

5 University, Bangalore for his support and motivation towards this work with his valuable inputs. amplifier for a global navigation satellite system, Journal of Semiconductors, vol. 31, no. 12, References [1]. Indian Regional Navigation Satellite System Signal In Space ICD for Standard Positioning Service (Version 1.0, ISRO-IRNSS-ICD-SPS-1.0), Indian Space Research Organization, June 2014, available at: last access: [2]. Sarang Thombre, Heikki Hurskainen, Jari Nurmi, Wideband, High Gain, High Linearity, Low Noise Amplifier for GNSS Frequencies with Compensation for Low Frequency Instability, Proc. of Advance satellite multimedia systems conference, [3]. Navneeta Deo, Design and Test of an L-Band (GNSS) Low Noise Amplifier and Limiter, Master s Thesis, Lund University, [4]. Md. Maruf Hossain, Design of RF Front End for Multi-Band Multi-System GNSS Receivers, Master s Thesis, [5]. Nimesh M. Prabhakar and A K. Sisodia, Low Noise Amplifier Design for Navigation Signal Receiver, International Journal of Engineering Development and Research vol. 2, 1, pp , [6]. Viranjay M. Srivastava, Ravinder Kumar, Low Noise Amplifier for 2.45 GHz Frequency Band at 0.18 μm CMOS Technology for IEEE Standard b/g WLAN International Journal of Intelligent Systems and Applications, vol. 9, pp.68-74, [7]. X.B.Mei, C.H.Lin A W-Band INGAAS/INALAS/INP HEMT Low-Noise Amplifier MMIC with 2.5DB Noise Figure and 19.4 DB Gain at 94GHz, Northrop Grumman Corporation One Space Park, Redondo Beach, CA 90278, [8]. Yu-na Su, Geng Li, Design of a Low Noise Amplifier of RF Communication Receiver for Mine, College of Computer Science and Technology, Henan Polytechnic University, JiaoZuo, , China, [9]. Yishay netzer, The Design of Low-Noise Amplifiers, Proceedings of the IEEE conference, vol. 69, no. 6, [10]. Yu-Lin Wei, Shawn S. H. Hsu, A Low-Power Low- Noise Amplifier for K-Band Applications, IEEE Microwave and Wireless Components Letters, vol. 19, no. 2, [11]. Prabir K. Saha, Subramaniam Shankar Analysis and Design of a 3-26 GHz Low-Noise Amplifier in SiGe HBT Technology, Proceedings of Radio and wireless Symposium, [12]. Muhammad Asif Zakariyya. Design of wide band Low Noise Amplifier for Antenna Testing System, International Journal of Computer Applications, vol.71 No.11, [13]. Li Bing, Zhuang Yiqi, Li Zhenrong, and Jin Gang, A 0.18 m CMOS dual-band low power low noise Author s profile: Gayathri K M is a Research scholar in the Department of Electronics and Communication Engineering, School of Engineering and Technology, Jain University, Bangalore. She has obtained her Bachelor s Degree in Medical Electronics from VTU, Bangalore in the year She has obtained her Master s Degree in VLSI and Embedded Systems from VTU, Karnataka in the year She is having 3.6 years of teaching experience. Her areas of interest are VLSI, Wireless communication, ASIC design, Analog and mixed Signal design. Dr. Thangadurai. N is working with Department of Electronics and Communication Engineering, Jain University, Bangalore. He has obtained his Ph.D in Wireless Sensor Networks from Bharathiar University, Coimbatore in the year He has obtained his Bachelor s Degree in Electronics and Communication Engineering from Coimbatore Institute of Technology under Bharathiar University in the year He has obtained his Master s Degree in Applied Electronics from Mohamed Sathak Engineering College under Anna University in the year He has published 50 research papers in both International and National Journals and conferences. He has supervised number of undergraduate and postgraduate Students for their project completion. His research interests are Networking, Wireless Communication, Satellite Communications, Mobile Adhoc and Wireless Sensor Networks, Embedded Systems, Telecommunication Engineering and Navigation System. He is also a Life member of following professional bodies like ISCA, ISTE, IETE, IAENG and IACSIT. 5356