Simultaneous photonic generation of multiple chirp and unchirp microwave waveform with frequency multiplying capability for optical beam forming system
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A photonic technique based on the Mach–Zehnder Modulator and the dual parallel Mach–Zehnder modulator is proposed for the simultaneous generation of multiple chirp and unchirp microwave waveform with frequency multiplying capability for efficient beam steering applications. There is provision to obtain a single chirp signal of a particular center frequency and chirp rate from a multiple chirp signal without any alternation in the experimental setup. In the proposed methodology, the PIN photodetector is used for the detection of 12 GHz unchirp microwave waveform showing the frequency doubling characteristics and the balance photodetector is used for the detection of multiple chirp signal with frequency components 6, 12, and 18 GHz. The same experimental setup is used to generate dual linear chirp microwave signal of 12 GHz center frequency. This can be achieved by adjusting the bias voltage of the phase modulator. Time bandwidth product and bandwidth of the signal are 18.33 and 410 MHz, respectively. This technique is tunable in frequency, but the generation of higher frequency microwave signals is limited by the speed and bandwidth of the Mach–Zehnder Modulator and photodetector. The novelty of our proposed scheme is that we are going to drive MZM by chirp RF signal to multiply the chirp rate in manifold. To the best of our knowledge the effect of chirp microwave signal on photonic highly steerable beam forming system has not yet been studied experimentally in past, which we are targeting under this paper. It is expected that the range of beam steering performance should be improved substantially as compared to previously reported results.
KeywordsDual parallel Mach–Zehnder modulator Frequency multiplication Ku-band Multiple chirp signal Photonic feeding antenna Beam steering
This work is financially supported by Space Applications Centre, Indian Space Research Organization (ISRO), Ahemdabad, India with ISRO respond project entitled “A novel Mach–Zehnder Modulator based integrated photonic highly steerable beam-forming system for broadband satellite communication link”. This work is carried out under project number: ISRO/(10)/2018-2019/571/ECE(Grant No. DS-2B-13012(2)/13/2018). Authors would like to thanks Mr R K Bahl, Head, Optical Communication Division, Satcom and Navigation Payload Area, Space Application Centre, Indian Space Research Organization (ISRO), Ahmedabad 380053, for necessary experimental support. Authors would also like to thank NPIU MHRD for funding the project title “Generation of chirped arbitrary microwave waveforms with enhanced performance using photonic technique” with project application No. 1-5744809099. This project is approved under “TEQIP Collaborative Research Scheme”.
- Ashrafi, R., Li, M., Azana, J.: Femtosecond optical waveform generation based on space-to-time mapping in long period gratings. In: IEEE Conference, pp. 104–105 (2012)Google Scholar
- Cook, C.E., Bernfeld, M.: Radar Signals. Academic Press, New York (1967)Google Scholar
- Griffiths, H.D., Bradford, W.J.: Digital generation of high time-bandwidth product linear FM waveforms for radar altimeters. IEE Proc.-F 139(2), 160–168 (1992)Google Scholar
- Skolnik, M.I.: Introduction to Radar Systems. McGraw-Hill, New York (2001)Google Scholar
- Song, T.K., Jeong, Y.K.: Ultrasound imaging system and method based on simultaneous multiple transmit-focusing using weighted orthogonal chirp signals. U.S. Patent 7 066 886 (2006)Google Scholar
- Zhao, Y, Yang, J., Zhang, Y., Lin, Q., Chen, Z.: Implementation of multi-waveband, high-precision, wideband waveform generator based on DDWS for antenna channel characteristics test. In: 2016 Progress in Electromagnetic Research Symposium, pp. 444–449 (2016)Google Scholar