Merged simulation procedure for W-band imaging systems

Gutiérrez, Jaime; Pascual, Juan Pablo; Tazón, A.

doi:10.1002/mmce.21284

Cited by 2 publications

(3 citation statements)

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“…Therefore, the definition of an ad hoc procedure is required. For the total power mode, the simulation procedure (described in [15]) starts with the definition of the Equivalent Noise Bandwidth of a radiometer chain with gain G(f), given by [8]:…”

Section: Radiometer Simulations: Total Power and Dicke Modesmentioning

confidence: 99%

“…In this work, the design and characterization of W-band radiometers with superheterodyne and direct detection topologies are presented, operating as a total power radiometer and as a Dicke radiometer, allowing by extrapolation the evaluation of W-band instruments composed of a group of those receivers. Previous works have presented the development and characterization of the opto-mechanical components (antenna front-end) and the design and optimization of a polarimeter in W-band [13,14], as well as the use of a total power radiometer with direct detection in W-band for imaging systems [15]. This paper is structured as follows: In Section 2, the two topologies under consideration (super-heterodyne and direct detection) are described.…”

Section: Introductionmentioning

confidence: 99%

“…Figure15. Gain and noise figure of the W-band receiver composed of the two W-band amplifiers with the isolator, the BPF, 9 dB attenuation, the mixer and the IF amplifier.…”

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confidence: 99%

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Performance Assessment of W-Band Radiometers: Direct versus Heterodyne Detections

et al. 2021

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W-Band radiometers using intermediate frequency down-conversion (super-heterodyne) and direct detection are compared. Both receivers consist of two W-band low noise amplifiers and an 80-to-101 GHz filter, which conforms to the reception frequency band, in the front-end module. The back-end module of the first receiver comprises a subharmonic mixer, intermediate frequency (IF) amplification and a square-law detector. For direct detection, a W-Band detector replaces the mixer and the intermediate frequency detection stages. The performance of the whole receivers has been simulated requiring special techniques, based on data from the experimental characterization of each subsystem. In the super-heterodyne implementation a local oscillator at 27.1 GHz (with 8 dBm) with a x3 frequency multiplier is used, exhibiting an overall conversion gain around 48 dB, a noise figure around 4 dB, and an effective bandwidth over 10 GHz. In the direct detection scheme, slightly better noise performance is obtained, with a wider bandwidth, around 20 GHz, since there is no IF bandwidth limitation (~15 GHz), and even using the same 80-to-101 GHz filter, the detector can operate through the whole W-band. Moreover, W-band detector has higher sensitivity than the IF detector, increasing slightly the gain. In both cases, the receiver performance is characterized when a broadband noise input signal is applied. The radiometer characteristics have been obtained working as a total power radiometer and as a Dicke radiometer when an optical chopper is used to modulate the incoming signal. Combining this particular super-heterodyne or direct detection topologies and total power or Dicke modes of operation, four different cases are compared and discussed, achieving similar sensitivities, but better performances in terms of equivalent bandwidth and noise for the direct detection radiometer. It should be noted that this conclusion comes from a particular set of components, which we could consider as typical, but we cannot exclude other conclusions for different components, particularly for different mixers and detectors.

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Section: Radiometer Simulations: Total Power and Dicke Modesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Performance Assessment of W-Band Radiometers: Direct versus Heterodyne Detections

et al. 2021

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Theoretical analysis and design of G-band extended interaction klystron amplifier

Zeng¹,

Ma²,

Hu³

et al. 2019

Acta Phys. Sin.

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Extended interaction klystron is a very important millimeter-wave and sub-millimeter-wave vacuum electron device with many actual and potential applications, such as space-borne cloud profiling radar, communication, imaging system, precision guided missiles, etc. Kinematical theory and space charge wave theory are extensively used to analyze the bunching process of electrons. Kinematical theory is precise when electron beam is especially small because the influence of space charge effect is ignored, while space charge wave theory is accurate when the modulation of electron beam is small since it is based on the premise of small amplitude. Based on kinematical theory, law of induce current, principle of charge conservation in a one-dimensioanl mode and small signal condition, the influence of electron beam on standing wave electric field in multiple-gap cavity is analyzed, and the expression of beam-loading conductance and beam-loading susceptance in multiple-gap cavity are derived. The influence of the direct current transmit angle of single gap, the number of multiple gaps and the direct current transmit angle of between center of adjacent gaps on beam-loading conductance and beam-loading susceptance are analyzed. The results show that the beam-loading conductance and beam-loading susceptance of multiple-gap cavity can change to a bigger extent when the number of cavity gaps is bigger, which means that the maximum beam-wave conversion efficiency and the range of loaded frequency increase with the number of cavity gaps increasing. The results also show that the direct current transmit angle between centers of adjacent gaps is the most important parameter for the beam-wave interaction effect. Based on the above analysis, a G-band extended interaction klystron amplifier consisting of three five-gap cavities is designed by an three-dimensional PIC code. An output power of 225.5 W at 217.94 GHz with an efficiency of 6.26%, whose gain and 3 dB bandwidth are 30.5 dB and 470 MHz respectively, is obtained by simulation. This study is of great significance for the physical design and process in engineering the G-band extended interaction klystron amplifier.

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Merged simulation procedure for W-band imaging systems

Cited by 2 publications

References 12 publications

Performance Assessment of W-Band Radiometers: Direct versus Heterodyne Detections

Performance Assessment of W-Band Radiometers: Direct versus Heterodyne Detections

Theoretical analysis and design of G-band extended interaction klystron amplifier

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