Development of a Time Domain Microwave System for Medical Diagnostics

Zeng, Xuezhi; Fhager, Andreas; He, Zhongxia Simon; Persson, Mikael; Linnér, Peter; Zirath, Herbert

doi:10.1109/tim.2014.2326277

Cited by 39 publications

(34 citation statements)

References 20 publications

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“…Time-domain (TD) analysis techniques (such as the one employed here) enjoy a relative advantage in this arena over frequency-domain (FD) ones because the latter requires cumbersome and expensive VNA hardware [5]. Nevertheless, TD approaches would stand to benefit from hardware improvements that include optimizing the recording oscilloscope [14]- [16], new pulse generation technologies [17], [18], and better-integrated antenna arrays and switching systems, to which we turn our attention in this paper.…”

Section: Introductionmentioning

confidence: 99%

“…Other groups, including our own, have opted for a TD system [7], [13], [14], in which short-duration broadband pulses are generated and used to illuminate the breast. The scattered signals are recorded (usually these are bistatic or multistatic signals as the switching time required for a monostatic system in the TD is a limiting factor) with an oscilloscope.…”

Section: Introductionmentioning

confidence: 99%

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A Time-Domain Microwave System for Breast Cancer Detection Using a Flexible Circuit Board

Santorelli

Porter

Kang

et al. 2015

IEEE Trans. Instrum. Meas.

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We present the design of a flexible multilayer circuit board for use in a custom-built microwave system for breast health monitoring. The flexible circuit features both an integrated solid-state switching network and 16 wideband antennas, which transmit short-duration pulses into the breast tissues and receive the backscattered responses. By integrating the switching matrix and the antenna array on the same substrate, we reduce the overall cost and size of the system in comparison with previously demonstrated systems in the literature. We characterize the performance of the flexible circuit board using our clinically tested experimental system and demonstrate its functionality through successful imaging of dielectrically realistic breast phantoms that simulate the presence of a tumor. This represents a step toward a more patient-friendly, compact, cost-effective, and wearable design in contrast to previous systems in the literature that required a clinical table or used bulky rigid antenna housings and electromechanical switching networks. Emily Porter (S'11) received the B.Eng. and M.Eng. degrees in electrical engineering from McGill University, Montreal, QC, Canada, in 2009 and 2010, respectively, where she is currently pursuing the Ph.D. degree in electrical engineering.She is involved in research on applied and computational electromagnetics. Her current research interests include the medical applications of microwaves, flexible antennas, the design of realistic breast phantoms and models, and the development of a wearable prototype for breast health monitoring using microwave radar.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Time-Domain Microwave System for Breast Cancer Detection Using a Flexible Circuit Board

Santorelli

Porter

Kang

et al. 2015

IEEE Trans. Instrum. Meas.

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“…To get equivalent signalto-noise ratio performance, time domain systems may need to use multiple signal pulses to get adequate performance when deep targets need to be analysed. A time domain system is highly likely to have poor performance if not carefully designed, particularly for a complicated measurement scenario, like medical imaging [32].…”

Section: Background and Motivationmentioning

confidence: 99%

Design of wideband microwave frontend for microwave-based imaging systems

Marimuthu¹

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Microwave imaging has been investigated in the last few years as an attractive complement to current diagnostic tools for medical applications due to its low-cost, portability and nonionization radiation. Research to verify the feasibility of microwave imaging systems for medical applications is conducted using a Vector Network Analyser (VNA) as the microwave transceiver. The VNA is usually bulky and expensive, and thus prevents microwave imaging systems from being low-cost and portable. A necessary condition to turn microwave imaging into a mass screening diagnostic tool is to replace the VNA with a low-cost portable unit that can characterise, generate, transmit and receive signals, across a wideband with large dynamic range and stability. Tissues in the human body are lossy at microwave frequencies, and hence microwave signals undergo high attenuation when penetrating the human tissues during the process of imaging. Using a wider frequency spectrum provides better resolution, but low frequencies penetrate further into the body. As a trade-off between the required signal penetration and image resolution, microwave frequencies within the band 0.5-4 GHz have been used in many medical applications, such as head, torso, and breast imaging.Thus, the desired generic microwave transceiver for microwave-based medical imaging should cover this wide frequency band.This thesis proposes two versions of a reconfigurable low-cost portable broadband RF frontend medical imaging systems based on Software Defined Radio (SDR) and in doing so makes four contributions to the field of microwave imaging systems. The first contribution is the design of a low-cost reconfigurable microwave transceiver based on software defined radar (SDRadar). A RF broadband circulator used to separate the transmitted and received signal and a virtual ultra-wideband (UWB) time domain pulse is generated by coherently adding multiple frequency spectrums together. To verify the proposed SDRadar system for medical imaging, experiments were conducted using a circular scanning system and directional antenna. An image reconstruction algorithm used to generate and verify the images of the target embedded in a phantom developed with liquid emulating the average properties of different human tissues using the measurement data. The system successfully detects and localise small targets at different locations in the phantom.The above broadband circulator, however, limited the isolation between the transmitted and received signal, and the system lacked a calibration process. Hence, the proposed system is unable to image more complex human tissues.iii The second contribution of the thesis is the design of Vector Network Analyzer (VNA) by using the above SDR called Software defined VNA (SDVNA) with a highly directive broadband directional coupler (0.5-4 GHz). However, using a directional coupler with a single-receiver single-transmitter the conventional open/short/match/thru calibration technique is not applicable, and thus, it is re-developed to take into ac...

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“…To generate the required incident signals with wideband frequency, stepfrequency-continuous-wave (SFCW) is usually used since it is difficult to generate single pulse with wideband spectrum. The generation of SFCW signals can be easily achieved by using VNA, however, under the requirement of constructing portable and low-cost microwave imaging system, the usage of VNA is replaced by portable transceiver [16], [56] or softwaredefined-radar (SDR) technique [52]- [55]. Either portable transceiver or SDR system needs to use wide frequency band which implies large number of pulses with stepped frequencies has to be generated.…”

Section: Drawbacks Of the Current Algorithmsmentioning

confidence: 99%

“…Since it is difficult to generate a single pulse with more than 100% fractional bandwidth, stepped frequency continuous wave (SFCW) are usually used in the signal generator's design. The usage of wideband signal might be suitable for the systems using vector network analyser (VNA) as the signal generator [36], [40], however, to design portable and low-cost microwave imaging systems, the bulky and expensive VNA need to be replaced by portable transceivers [16], [56] or software defined radio (SDR) [52]- [55]. In the portable transceiver or SDR designs, wideband signal implies more stepped frequencies, and the large number of stepped frequencies implies high performance sampling circuit or analog-to-digital converter (ADC) have to be designed [16], [56]; and longer calibration time was required in the system [52] since for each stepped frequency, the system need to implement the calibration procedure one time.…”

Section: Challenges and Problems In Radar-based Microwave Imaging Tecmentioning

confidence: 99%

Processing and imaging techniques for microwave-based head imaging

Guo¹

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Development of a Time Domain Microwave System for Medical Diagnostics

Cited by 39 publications

References 20 publications

A Time-Domain Microwave System for Breast Cancer Detection Using a Flexible Circuit Board

A Time-Domain Microwave System for Breast Cancer Detection Using a Flexible Circuit Board

Design of wideband microwave frontend for microwave-based imaging systems

Processing and imaging techniques for microwave-based head imaging

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