Multipixel cameras represent an emerging topology for arrays receivers, improving speed and accuracy of both security scanning systems and radioastronomical sky surveys by means of a matrix of phased elements. Difficulties in the generation and proper distribution to each pixel of the local oscillator signal still limit their use to frequency ranges below a few GHz or at least seriously affect the complexity of the implementable cameras. This work presents a full comparison between two possible system architectures, alternatively based on LO frequency multiplication or subharmonic mixing strategies, aiming to overcome the aforesaid limitations: design and performance of two compact test vehicles in MMIC technology, both operating in the Q-band frequency range with ultrabroadband IF section, are reported. 1. Introduction Array receivers have been adopted since the beginning of the 90’s in radioastronomical applications [1] and, more recently, in security scanning systems, improving active and passive millimetre-wave imaging capabilities [2]. In radioastronomical applications, this kind of receivers is usually placed at the focus of a large radiotelescope antenna and it is mainly used to survey large areas in a more efficient way than single-pixel receivers. Array receivers can be roughly classified into three different types: focal plane arrays (FPAs), which incorporate distinct superheterodyne receivers performing a spectroscopic analysis of the incoming signal; bolometric arrays (BAs), achieving an integral measure of the total channel power; phased array feeds (PAFs) consisting of a matrix of receiving elements fed by the same local oscillator and then digitally combined [3]. Major research efforts are currently devoted to the latter receiver architecture, exhibiting two key advantages over conventional multibeam horn feeds: firstly it enables the radiotelescope to support many simultaneous beams on the sky, thus increasing the instrument speed; secondly, it offers the opportunity to properly shape the pattern of the feed array in order to match the optical configuration of the telescope [4]. The major drawback of a PAF, often limiting its use for frequency ranges above a few GHz, is however the necessary requirement of distributing the same LO signal to each pixel, without loss of synchronism between different paths; the research for new circuit topologies allowing to overcome this limitation represents the main purpose of this work. Possible strategies have the common feature of reducing the main local oscillator operating frequency, thus
References
[1]
J. J. Condon, J. J. Broderick, G. A. Seielstad, K. Douglas, and P. C. Gregory, “A 4.85？GHz sky survey. I—maps covering delta between 0 and +75？deg,” Astronomical Journal, vol. 97, pp. 1064–1073, 1998.
[2]
J. Richter, D. N？tel, F. Kl？ppelt, J. Huckt, H. Essent, and L. P. Schmidt, “A multi-channel radiometer with focal plane array antenna for W-band passive millimeterwave imaging,” in Proceedings of the 2006 IEEE MTT-S International Microwave Symposium Digest, pp. 1592–1595, June 2006.
[3]
D. T. Emerson and J. M. Payne, Multi-Feed Systems for Radio Telescopes, Conference Series, Astronomical Society of the Pacific, San Francisco, Calif, USA, 1995.
[4]
B. Veidt and P. Dewdney, “Development of a phased-array feed demonstrator for radio telescopes,” in Proceedings of the 11th International Symposium on Antenna Technology and Applied Electromagnetics, Saint-Malo, France, June 2005.
[5]
http://www.home.agilent.com.
[6]
S. Maas, The RF and Microwave Circuits Design Cookbook, Artech House, Norwood, Mass, USA, 1998.
[7]
P. Colantonio, F. Giannini, G. Leuzzi, and E. Limiti, “On the optimum design of microwave active frequency doublers,” in Proceedings of the IEEE MTT-S International Microwave Symposium Digest, pp. 1423–1426, May 1995.
[8]
C. K？rnfelt, R. Kozhuharov, H. Zirath, and I. Angelov, “High-purity 60-GHz-band single-chip 8 multipliers in pHEMT and mHEMT technology,” IEEE Transactions on Microwave Theory and Techniques, vol. 54, no. 6, pp. 2887–2898, 2006.
[9]
H. Okazaki, T. Nakagawa, and K. Araki, “A low-power ku-band GaAs monolithic frequency quadrupler,” in Proceedings of the 29th European Microwave Conference, vol. 2, pp. 353–356, Munich, Germany, October 1999.
[10]
S. A. Maas, Nonlinear Microwave and RF Circuits, Artech House, Norwood, Mass, USA, 2nd edition, 2003.
[11]
M. Ito, S. Kishimoto, T. Morimoto, Y. Hamada, and K. Maruhashi, “Highly integrated 60？GHz-band 12 multiplier MMIC,” in Proceedings of the 2006 IEEE MTT-S International Microwave Symposium Digest, pp. 1697–1700, June 2006.
[12]
P. Colantonio, F. Giannini, G. Leuzzi, and E. Limiti, “Non-linear design of active frequency doublers,” International Journal of RF and Microwave Computer-Aided Engineering, vol. 9, no. 2, pp. 117–128, 1999.
[13]
T. H. Chen, K. W. Chang, S. B. T. Bui, L. C. T. Liu, G. S. Dow, and S. Pak, “Broadband single- and double-balanced resistive HEMT monolithic mixers,” IEEE Transactions on Microwave Theory and Techniques, vol. 43, no. 3, pp. 477–484, 1995.
[14]
S. Maas, M. Kintis, F. Fong, and M. Tan, “Broadband planar monolithic ring mixer,” in Proceedings of the IEEE Microwave and Millimeter-Wave Monolithic Circuits Symposium, pp. 51–54, June 1996.
[15]
D. Schneiderbanger, M. Nezadal, M. Sterns, R. Rehner, S. Martius, and L. P. Schmidt, “A double-balanced diode mixer with multi-decade bandwidth up to 119？GHz,” in Proceedings of the 1st European Wireless Technology Conference (EuWiT '08), pp. 5–8, October 2008.
[16]
M. Yu, R. H. Walden, A. E. Schmitz, and M. Lui, “Ka/Q-band doubly balanced MMIC mixers with low LO power,” IEEE Microwave and Wireless Components Letters, vol. 10, no. 10, pp. 424–426, 2000.
[17]
G. Felic and E. Skafidas, “An integrated transformer balun for 60？GHz silicon RF IC design,” in Proceedings of the International Symposium on Signals, Systems and Electronics (ISSSE '07), pp. 541–542, August 2007.
[18]
C. M. Lin, C. H. Lin, J. C. Chiu, and Y. H. Wang, “An ultra-broadband doubly balanced monolithic ring mixer for Ku- to Ka-band applications,” IEEE Microwave and Wireless Components Letters, vol. 17, no. 10, pp. 733–735, 2007.
[19]
C. J. Trantanella, “Ultra-small MMIC mixers for K- and Ka-band communications,” in Proceedings of the 1999 IEEE MTT-S International Microwave Symposium Digest, vol. 2, pp. 647–650, June 2000.
[20]
B. C. Henderson, “Mixers in microwave systems (part 2),” Tech Note of Watkins-Johnson Company, WJ Communications, San Jose,Calif, USA, 2001.
[21]
M. Q. Lee, S. M. Moon, K. K. Ryu, D. P. Jang, and I. B. Yom, “Subharmonically pumped image rejection mixer for K-band applications,” in Proceedings of the Gallium Arsenide Applications Symposium, Amsterdam, The Netherlands, October 2004.
[22]
P. C. Yeh, W. C. Liu, and H. K. Chiou, “Compact 28-GHz subharmonically pumped resistive mixer MMIC using a lumped-element high-pass/band-pass balun,” IEEE Microwave and Wireless Components Letters, vol. 15, no. 2, pp. 62–64, 2005.
[23]
J. B. Beyer, S. N. Prasad, R. C. Becker, J. E. Nordman, and G. K. Hohenwarter, “MESFET distributed amplifier guidelines,” IEEE Transactions on Microwave Theory and Techniques, vol. 32, no. 3, pp. 268–275, 1984.
[24]
C. Paoloni and S. Kosslowski, “New approach on the design of travelling wave amplifier,” in Proceedings of the 34th Midwest Symposium on Circuits and Systems, vol. 1, pp. 414–417, Monterey, Calif, USA, May 1991.
[25]
K. Narendra, E. Limiti, C. Paoloni, J. M. Collantes, and R. H. Jansen, “Cascaded distributed power amplifier with non-identical transistors and inter-stage tapered impedance,” in Proceedings of the 40th European Microwave Conference (EuMC '10), pp. 990–993, Paris, France, September 2010.
