Neel patel paper
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The document details the design and measurement of a high power amplifier (HPA) operating at 3.4 GHz for satellite transponders, emphasizing the importance of stability and impedance matching in its development. Using a BJT transistor, the design aimed to achieve specifications such as high gain, efficiency, and minimal distortion, despite encountering challenges in meeting all requirements. The conclusions highlight the insights gained from the design process and the need for further exploration of matching networks and device modeling.
![X. CONCLUSION
The power amplifier presented here doesn’t
meet many of the required specifications. Still a
Stable Power amplifier with certain loss of power has
been designed with proper matching networks. But
working on this design provided a lot on insight into
design of power amplifiers and the problems faced
when the specifications require designs to be
extremely competitive in terms of performance.
The choice of transistor in this power
amplifier has influenced the design specifications in
an unexpected manner. To make a power amplifier
utilizing this device, a wide variety of matching
networks should be explored along with an
appropriate device modelling in ADS. Also Complete
the Impedance Matching , Biasing Network ,
Harmonics Balance.
XI. ACKNOWLEDGEMENT
The Author thanks Prof.A.K Sisodia & Ast Prof.
Nimesh M. Prabhakar from L.J.Institute of
Engineering and Technology for technical discussion
& processing support without whom this paper would
never be complected.
XII. REFERENCES
[1] Tomohiro Senju, Takashi Asano, Hiroshi
Ishimura Microwave Solid-state Department “A
VERY SMALL 3.5 GHz 1 W MMIC POWER
AMPLIFIER WITH DIE SIZE REDUCTION
TECHNOLOGIES” Komukai Operations Toshiba
Corporation, Komukai, Toshiba-cho, Saiwai-ku,
Kawasaki 2 12-858 1, Japan-2001 IEEE, pp. 070-073
,ISBN:0-7803-7161-5/01.
[2] Kevin W. Kobayashi, YaoChung Chen, Ioulia
Smorchkova, Roger Tsai,Mike Wojtowicz, and Aaron
Oki “A 2 Watt, Sub-dB Noise Figure GaN MMIC
LNA-PA Amplifier with Multi-octave Bandwidth
from 0.2-8 GHz” 2007 IEEE - SIRENZA
MICRODEVICES, pp.619 -622,ISBN:1-4244-0688-
9/07.
[3] Paul saad, christian fager, hossein mashad nemati,
haiying cao, herbert zirath and kristoffer andersson ”
A highly efficient 3.5 GHz inverse class-F GaN
HEMT power amplifier” European Microwave
Association International Journal of Microwave and
Wireless Technologies, 2010, 2(3-4), pp.317–
332,DOI:10.1017.
[4] Bilkent University, Nanotechnology Research
Center, Bilkent, Ankara, Istanbul Technical
University, Electrical & Electronics Faculty,Maslak,
Istanbul, Turkey ” Design of High Power S-Band
GaN MMIC Power Amplifiers for WiMAX
Applications” 2011 IEEE, pp.01-04,ISBN:978-1-
4244-6051-9/11.
[5] Ahmed Sayed, Georg Boeck Microwave
Engineering, Berlin University of Technology
Einsteinufer 25, 10587 Berlin, Germany ” 5W
Highly Linear GaN Power Amplifier with 3.4 GHz
Bandwidth”European Microwave Integrated Circuits
Conference 2007 EuMA , pp.631 – 634,ISBN:978-2-
87487-002-6.
[6] U. K. Mishra, P. Parikh, and Y.-F. Wu,
“AlGaN/GaN HEMTs−An overview of device
operations and applications”, Proceedings of the
IEEE, vol. 90, no. 6, June 2002, pp. 1022–
1031,ISBN:2230-7109.
[7] U. K. Mishra, L. Shen, T. E. Kazior, and Y.-F.
Wu, “GaN-Based RF Power Devices and
Amplifiers”, Proceedings of the IEEE, vol. 96, no. 2,
February 2008, pp. 287 – 305,ISBN:2230-9543.
[8] S. Keller et al., “Gallium Nitride Based High
Power Heterojunction Field Effect Transistors:
Process Development and Present Status at UCSB”,
IEEE Transactions on Circuits and Systems, vol. 48,
no. 3, March 2001, pp. 552 – 559,ISBN:2278-0181.
[9] U.Schmid et al., “GaN devices for communication
applications: evolution of amplifier architectures”,
International Journal of Microwave and Wireless
Technologies, Cambridge University Press and the
European Microwave Association, 2010, pp. 85–
93,DOI:10.1088/1674-4926/32/9/094003.
[11] Nemati, H.; Fager, C.; Thorsell, M.; Herbert, Z
“High-efficiency LDMOS power-amplifier design at
1 GHz using an optimized transistor model”. IEEE
Trans. Microw. Theory Tech., 57 (7) (2009), pp.
1647–1654,ISSN:3840-7001.
[12] Rollett, J. “Stability and power-gain invariants of
linear two ports”. IEEE Trans. Circuit Theory, 9 (1)
(2010), pp. 29–32,ISBN:978-1-4673-1088-8/12.
[13] Kim, J.; Konstantinou, K.”Digital predistortion
of wideband signals based on power amplifier model
with memory”. Electron. Lett., 37 (2001), pp. 1417–
1418, ISSN:0-7803-8331-1/04.
[14] Nagy, W.; Brown, J.; Borges, R.; Singhal, S.
“Linearity characteristics of microwave-power GaN
HEM”. IEEE Trans. Microw, 51 (2) (2012), pp.660–
664, ISSN:0018-9480.](https://image.slidesharecdn.com/neelpatelpaper-160510105749/85/Neel-patel-paper-7-320.jpg)
Neel patel paper
- 1. Design Of High Power Amplifier At 3.4 GHz For Satellite Transponder (IRNSS) Patel Neel K. Prof. Anil K Sisodia Ast Prof. Nimesh M Prabhakar Department of Master Engineering In Communication System Engineering, L. J. Institute of Engineering and Technology, Gujarat Technological University, Ahmedabad, Gujarat patel.neel2810@gmail.com Abstract This paper gives a step-by-step of the design, simulation and measurement of a Power Amplifier(PA) operating frequency from 2.5GHz to 4.5GHz. The design of Class A Power amplifier was performed in Agilent ADS and the performance was tested with SZA3044Z BJT. Key Words: RF Power Amplifier, Bipolar Junction Transistor(BJT), IRNSS, High Gain I. INTRODUCTION In a communication satellite serving the earth, the transponder transforms the received signals into forms appropriate for the transmission from space to earth. The transponder may be simply a repeater that amplifies and frequency signals. In this paper, the technologies of the major transponder elements are presented and amplifying devices. One of the key elements of any spacecraft transponder is the output transmitter, consisting of a high power amplifier (HPA) and the associated power supply. The amplifier is operated at or near saturation (maximum output power level) to attain a high overall efficiency of converting dc energy from the power supply into useful radio frequency (RF) energy that carries information. The transmitter is required to amplify the wanted signal without distortions and without other impairments which would decrease the usefulness of the signal. Two types of amplifiers (transmitters) are in common use, electron beam devices (commonly TWTAs) and solid state power amplifiers (SSPAs). For the TWTAs, the electrical power supply is often required to supply a number of high voltages (in the multikilovolt range), which presents a series of technology and design challenges. show in fig 1. Fig 1 – Transponder power amplifier diagram II. DESIGN APPROACH The wireless communications in satellite transponder increasing demands on systems designs. A critical element in Radio Frequency (RF) front ends is the Power Amplifier (PA). Main specifications for PA design include high linearity, better gain and efficiency. This paper describes the process of designing a single stage classA Power Amplifier for operation in the 2.5-4.5 GHz band. The active device specified for this design was a Rfmd SZA3044Z BJT. Table I shows the performance specifications for the designed Power amplifier. TABLE I TARGET SPECIFICATION Parameter Symbol Specification Frequency range fo 2.5-4.5 GHz Gain S21 ≥15dB Input return loss S11 ≤ -10dB Output return loss S22 ≤ -10dB Input/output Impedance Z0 50Ω Output power P0 1W
- 2. III. STABILITY CONSIDERATION Before PA design, it is important to determine the stability of the transistor. The stability of an amplifier is very important in the design and if not taken care, can create self-oscillation of the device due to reflected wave. Amplifier is not reliable when it is unstable condition. The stability of a circuit is characterized by stability factor. The transistor is stable when K>1 and ∆<1. Fig 2- Stability simulation After simulation ,the value of stability factor (K) is 6.673(K>1). So, now the transistor is in stable region. STABILITY FACTOR, K (SHOULD BE >1) Fig 3- Stability result IV. MATCHING NETWORK DESIGN Impedance matching is required to maximize the power transfer and minimize the reflections. Smith chart is used for impedance matching. According to maximum power transfer theorem, maximum power delivered to the load when the impedance of load is equal to the complex conjugate of the impedance of source (ZS=ZL*). A.INPUT MATCHING NETWORK The first set of measurements we are taken for S11 with the device mounted on the board and biased, but without matching networks. These measurements were de-embedded in ADS to obtain the input impedance at the device terminal. Fig 4- Input matching network The circuit was then conjugate matched from this point to the 50Ω impedance presented by the trace line. The input matching network shown in Figure 3, was designed using the Smgamma function in ADS. The input matching network uses a series inductor and parallel capacitor. A parallel capacitor is the value of 0.5pF and series inductor is the value of 1.4nH. A lumped component matching at 3.4GHz is a viable option but it would not provide the option of tuning. Fig 5- Input impedance result B. OUTPUT MATCHING NETWORK To design the output matching network, S22 of the biased, unmatched system was measured and de- embedded back to the device terminals. Simulations were then performed to determine the impedance presented to the drain that would maximize small signal gain. The matching network was designed in the same fashion as the input matching network. This method gave several different optimal load impedances, indicating that trade-offs would be necessary to meet all specifications. The output matching network shown in Figure 5, was designed using the Smgamma function in ADS.
- 3. Fig 6- Output matching network The output matching network uses a series inductor and parallel capacitor. A parallel capacitor is the value of 2.85 pF and series inductor is the value of 0.5nH. A lumped component matching at 3.4GHz is a viable option but it would not provide the option of tuning. Fig 8- Output impedance result INPUT RETURN LOSS AND OUTPUT RETURN LOSS Fig 9-S11 Fig 10- S22
- 4. Fig 11- S21 Gain Fig-14 S21 After Baising Gain Fig 13 S11 After Biasing Fig-15 After Baising Stability factor
- 5. VI. MEASURED RESULTS The complete schematic of the power amplifier is shown in the Figure. The performance results are using the Impedance Matching. Then After Matching the Most Important is Biasing Network . All Results Are including in below Table. VII. HARMONIC DISTORTION Harmonic distortion means the presence of frequency components in the output waveform which are not present in the input signal. Due to non linearity amplification of all the portion of positive and negative half cycles is not same and it causes the output waveform to be different from input waveform. When the input signal is applied to a transistor the non-linear characteristics causes the positive half of the signal to be amplified more than negative half cycle. Due to this output signal signal contains fundamental frequency components and some undesired frequency components, which are integral multiple of input signal frequency. These additional frequency components are called harmonics. Hence the output is said to be distorted, this is called harmonic distortion. VIII. SECOND ORDER HARMONICS: For linear amplification, the dynamic transfer characteristics relation b/w Ib and Ic which is known as transfer characteristic must be linear. To evaluate the second harmonic distortion assume that the dynamic transfer characteristics of the transistor is parabolic (non-linear ) in nature rather than (linear). Parameter Symbol Specification Measured results After Impedance Matching Measured results After Biasing Network Gain S21 ≥15dB 26.412dB 27.064dB Input return loss S11 ≤ -10dB -39.873dB -15.440dB Output return loss S22 ≤ -10dB -49.342dB -15.725dB Input/output Impedance Z0 50Ω 50Ω 50Ω
- 6. IX. HARMONIC BALANCE IN ADS: Fig 17 dBm(vout) Fig 19 1st Harmonic Fig 18 Gain Harmonic Fig 20 1st & 3rd Harmonic
- 7. X. CONCLUSION The power amplifier presented here doesn’t meet many of the required specifications. Still a Stable Power amplifier with certain loss of power has been designed with proper matching networks. But working on this design provided a lot on insight into design of power amplifiers and the problems faced when the specifications require designs to be extremely competitive in terms of performance. The choice of transistor in this power amplifier has influenced the design specifications in an unexpected manner. To make a power amplifier utilizing this device, a wide variety of matching networks should be explored along with an appropriate device modelling in ADS. Also Complete the Impedance Matching , Biasing Network , Harmonics Balance. XI. ACKNOWLEDGEMENT The Author thanks Prof.A.K Sisodia & Ast Prof. Nimesh M. Prabhakar from L.J.Institute of Engineering and Technology for technical discussion & processing support without whom this paper would never be complected. XII. REFERENCES [1] Tomohiro Senju, Takashi Asano, Hiroshi Ishimura Microwave Solid-state Department “A VERY SMALL 3.5 GHz 1 W MMIC POWER AMPLIFIER WITH DIE SIZE REDUCTION TECHNOLOGIES” Komukai Operations Toshiba Corporation, Komukai, Toshiba-cho, Saiwai-ku, Kawasaki 2 12-858 1, Japan-2001 IEEE, pp. 070-073 ,ISBN:0-7803-7161-5/01. [2] Kevin W. Kobayashi, YaoChung Chen, Ioulia Smorchkova, Roger Tsai,Mike Wojtowicz, and Aaron Oki “A 2 Watt, Sub-dB Noise Figure GaN MMIC LNA-PA Amplifier with Multi-octave Bandwidth from 0.2-8 GHz” 2007 IEEE - SIRENZA MICRODEVICES, pp.619 -622,ISBN:1-4244-0688- 9/07. [3] Paul saad, christian fager, hossein mashad nemati, haiying cao, herbert zirath and kristoffer andersson ” A highly efficient 3.5 GHz inverse class-F GaN HEMT power amplifier” European Microwave Association International Journal of Microwave and Wireless Technologies, 2010, 2(3-4), pp.317– 332,DOI:10.1017. [4] Bilkent University, Nanotechnology Research Center, Bilkent, Ankara, Istanbul Technical University, Electrical & Electronics Faculty,Maslak, Istanbul, Turkey ” Design of High Power S-Band GaN MMIC Power Amplifiers for WiMAX Applications” 2011 IEEE, pp.01-04,ISBN:978-1- 4244-6051-9/11. [5] Ahmed Sayed, Georg Boeck Microwave Engineering, Berlin University of Technology Einsteinufer 25, 10587 Berlin, Germany ” 5W Highly Linear GaN Power Amplifier with 3.4 GHz Bandwidth”European Microwave Integrated Circuits Conference 2007 EuMA , pp.631 – 634,ISBN:978-2- 87487-002-6. [6] U. K. Mishra, P. Parikh, and Y.-F. Wu, “AlGaN/GaN HEMTs−An overview of device operations and applications”, Proceedings of the IEEE, vol. 90, no. 6, June 2002, pp. 1022– 1031,ISBN:2230-7109. [7] U. K. Mishra, L. Shen, T. E. Kazior, and Y.-F. Wu, “GaN-Based RF Power Devices and Amplifiers”, Proceedings of the IEEE, vol. 96, no. 2, February 2008, pp. 287 – 305,ISBN:2230-9543. [8] S. Keller et al., “Gallium Nitride Based High Power Heterojunction Field Effect Transistors: Process Development and Present Status at UCSB”, IEEE Transactions on Circuits and Systems, vol. 48, no. 3, March 2001, pp. 552 – 559,ISBN:2278-0181. [9] U.Schmid et al., “GaN devices for communication applications: evolution of amplifier architectures”, International Journal of Microwave and Wireless Technologies, Cambridge University Press and the European Microwave Association, 2010, pp. 85– 93,DOI:10.1088/1674-4926/32/9/094003. [11] Nemati, H.; Fager, C.; Thorsell, M.; Herbert, Z “High-efficiency LDMOS power-amplifier design at 1 GHz using an optimized transistor model”. IEEE Trans. Microw. Theory Tech., 57 (7) (2009), pp. 1647–1654,ISSN:3840-7001. [12] Rollett, J. “Stability and power-gain invariants of linear two ports”. IEEE Trans. Circuit Theory, 9 (1) (2010), pp. 29–32,ISBN:978-1-4673-1088-8/12. [13] Kim, J.; Konstantinou, K.”Digital predistortion of wideband signals based on power amplifier model with memory”. Electron. Lett., 37 (2001), pp. 1417– 1418, ISSN:0-7803-8331-1/04. [14] Nagy, W.; Brown, J.; Borges, R.; Singhal, S. “Linearity characteristics of microwave-power GaN HEM”. IEEE Trans. Microw, 51 (2) (2012), pp.660– 664, ISSN:0018-9480.