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A low-loss broadband quadrature signal generation network for high image rejection at millimeter-wave frequencies
, Article IEEE Transactions on Microwave Theory and Techniques ; 2018 ; 00189480 (ISSN) ; Alizadeh, A ; Coen, C. T ; Cressler, J. D ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
This paper presents a broadband low-loss quadrature-hybrid-based network that enhances the phase and the amplitude matching of quadrature signals. The performance of this network is investigated, and a detailed theoretical analysis is provided. Several stages of this network can be cascaded to generate broadband balanced quadrature signals. Each stage has a loss of 0.5 dB and enhances the image rejection ratio (IRR) by approximately 8 dB. Compared with the conventional polyphase quadrature signal generation methods, the proposed network enables lower insertion loss, wider bandwidth, and reduced sensitivity to process variations. To verify the theoretical analyses, two proof-of-concept...
Phase-noise measurement of microwave oscillators using phase-shifterless delay-line discriminator
, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 58, Issue 2 , January , 2010 , Pages 468-477 ; 00189480 (ISSN) ; Banai, A ; Sharif University of Technology
2010
Abstract
In this paper, a modified method based on the frequency discriminator technique for measuring phase noise of microwave oscillators is presented. In the proposed method, the phase shifter is omitted. In contrast, a 90° hybrid with one more channel containing a phase detector, and a low-noise amplifier is added to the measurement setup. It can be said that an in-phase/quadrature phase-noise detection has been developed. With the proposed method, tuning of the variable phase shifter is not needed anymore. Therefore, the measurement is done automatically, and as a result, the measurement time is decreased. Another considerable advantage of this method is that the method is theoretically...
An ultra-broadband direct demodulator for microwave FM receivers
, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 59, Issue 8 , August , 2011 , Pages 2131-2139 ; 00189480 (ISSN) ; Banai, A ; Sharif University of Technology
2011
Abstract
A new broadband frequency discriminator is introduced for demodulating the frequency modulated signals in the microwave frequency range. Direct demodulation with no need for tuning the center frequency of the resonance circuits is the most important advantage of the proposed technique. This technique uses the in-phase/quadrature demodulation, in some manner, without using any additional local oscillator for down conversion. Simulation of the proposed demodulator has been done with Advanced Design System software to evaluate and predict the system behavior. A setup based on the proposed method was designed and implemented in order to verify the accuracy of the theory. We tested the proposed...