Millimeter-Wave Near-Field Probe Designed for High-Resolution Skin Cancer Diagnosis

Töpfer, Fritzi; Dudorov, Sergey; Oberhammer, J.

doi:10.1109/tmtt.2015.2428243

Cited by 51 publications

(21 citation statements)

References 35 publications

(35 reference statements)

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“…8(c)) is the concentration of the electric field to the high-permittivity silicon slab. This is similar to the field concentration seen in dielectric rod waveguides [14], where the field concentration is more significant for larger permittivity values. Since Design E has a permittivity which decreases in three steps, over the relatively long matching regions, we note that the field widens around the lens as it propagates through the regions of lower permittivity.…”

Section: Wideband Analysis Of Planar Lenses With Three Matching Regionssupporting

confidence: 80%

“…This type of artificial dielectrics have since then been used in antenna design (e.g., [2,7]), for test samples with a known permittivity [14], and in the design of W-band phase shifters [23]. We here use this technique in order to achieve tailor-made permittivities for the matching regions in the proposed lens antennas by etching periodic square holes of width h and period p in a silicon wafer according to Fig.…”

Section: Tailor-made Effective Permittivity Regions In a Silicon Wafermentioning

confidence: 99%

“…The free-etched lenses are installed on a WR-10 waveguide. The tapered dielectric wedge transition was designed following [14], and minimizes reflections at the boundary between the feeding waveguide and the dielectric body of the lens throughout the W-band (75-110 GHz). The simplest design without any matching region is referred to as Design A.…”

Section: Overviewmentioning

confidence: 99%

“…Planar lenses have many similarities with non-planar lenses, where there are many good references, see e.g., [8][9][10][11][12][13]. High-resistivity silicon is an excellent dielectric material for millimeter-wave planar lenses, due to its very small losses and accurate micromaching fabrication processes [14,15]. However, homogeneous lenses of high permittivity materials, such as silicon, suffer from reflections at the airdielectric interface caused by the large difference in impedance compared to free-space (see e.g., [9]).…”

Section: Introductionmentioning

confidence: 99%

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Optimization of Micromachined Millimeter-Wave Planar Silicon Lens Antennas With Concentric and Shifted Matching Regions

Frid¹,

Töpfer²,

Bhowmik³

et al. 2017

PIER C

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Abstract-This paper presents a study of planar silicon lens antennas with up to three steppedimpedance matching regions. The effective permittivity of the matching regions is tailor-made by etching periodic holes in the silicon substrate. The optimal thickness and permittivity of the matching regions were determined by numerical optimization to obtain the maximum wideband aperture efficiency and smallest side-lobes. We introduce a new geometry for the matching regions, referred to as shifted matching regions. The simulation results indicate that using three shifted matching regions results in twice as large aperture efficiency as compared to using three conventional concentric matching regions. By increasing the number of matching regions from one to three, the band-averaged gain is increased by 0.3 dB when using concentric matching regions, and by 3.7 dB when using shifted matching regions, which illustrates the advantage of the proposed shifted matching region design.

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Section: Wideband Analysis Of Planar Lenses With Three Matching Regionssupporting

confidence: 80%

Section: Tailor-made Effective Permittivity Regions In a Silicon Wafermentioning

confidence: 99%

Section: Overviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optimization of Micromachined Millimeter-Wave Planar Silicon Lens Antennas With Concentric and Shifted Matching Regions

Frid¹,

Töpfer²,

Bhowmik³

et al. 2017

PIER C

Self Cite

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show abstract

“…Therefore, to achieve an accurate measurement, a high-quality mm-wave probe with submillimeter sensing depth and high lateral resolution is desired. In 2015, Topfer et al invented a broadband probe operating from 90 to 104 GHz[67], which consists of a dielectric-rod waveguide that is metallized and tapered towards the tip to achieve high resolution by concentrating the electric field in a small sample area. The sensing depth was from 0.3 to 0.4 mm, which is adapted for detecting early-stage skin tumors before metastasizing.…”

mentioning

confidence: 99%

Advances in Microwave Near-Field Imaging: Prototypes, Systems, and Applications

Shao

McCollough²

2020

IEEE Microwave

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Microwave imaging is a science which evolves from detecting techniques to evaluate hidden or embedded objects in a structure or media using electromagnetic (EM) waves in the microwave range (i.e., from 300 MHz to 300 GHz). Microwave imaging is often associated with radar detection such as target detection and tracking, weather pattern recognition, and underground surveillance which are far-field applications. In recent years, due to microwave's characteristic that allows penetration into optically opaque media, short-range applications including medical imaging, nondestructive testing and quality evaluation, through-the-wall imaging, and security screening have been utilized. Microwave near-field imaging occurs when detecting the profile of an object within the short-range: when the distance apart from the sensor to the object is from less than one wavelength to several wavelengths --This is coarse definition because the size of the antenna and the object is often comparable to the range between them.A near-field microwave imaging system attempts to reveal the presence of an object and/or an electrical property distribution by measuring the scattered field from many positions surrounding the object. Typically many sensors are placed near the object and either a quantitative or a qualitative algorithm is applied to the collected data. Over the past few decades, both the hardware and software components of a near-field microwave imaging system technology have attracted interest throughout the world. Due to limitations of hardware technology (unavailability of data acquisition apparatus), experimental microwave imaging is very challenging for the pioneers. Examples can be found are the canine kidney imaging experiment carried by Jacobi and Larsen in the 1970s [1]-[3], and active microwave imaging for horse kidney by Jofre and Bolomey [4]. In 1990s, researchers started being able to use microwave signal higher than 1 GHz in real imaging systems. One example is by Bolomey and Pichot, who developed a practical system [5] and designed a planar microwave camera, both operating at This paper has been accepted by IEEE Microwave Magazine and published on a future issue.2.45 GHz [6]. However, Probably due to the hardware cost, most of the studies (operating at a few GHz) were still focused on software only. The feasibility of using microwave approaches to image different types of objects have been tested and verified by simulations in a variety of applications. Further, work has been conducted on improving both quantitative and qualitative algorithms to improve simulated reconstruction results. Nowadays, benefitting from the hardware progress and reduction of their cost, researchers are eager to pursue real experimental validations instead of simulations, and, more unique prototypes and commercial systems have been built for various applications. These prototypes and systems are a result of years of dedicated work and it is important to review the advancements in developed prototype systems. The article will provide an overv...

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Adjunctive Diagnostic Methods for Skin Cancer Detection: A Review of Electrical Impedance‐Based Techniques

Anushree

Shetty

Kumar

et al. 2022

Bioelectromagnetics

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Skin cancer is among the fastest‐growing cancers with an excellent prognosis, if detected early. However, the current method of diagnosis by visual inspection has several disadvantages such as overlapping tumor characteristics, subjectivity, low sensitivity, and specificity. Hence, several adjunctive diagnostic techniques such as thermal imaging, optical imaging, ultrasonography, tape stripping methods, and electrical impedance imaging are employed along with visual inspection to improve the diagnosis. Electrical impedance‐based skin cancer detection depends upon the variations in electrical impedance characteristics of the transformed cells. The information provided by this technique is fundamentally different from other adjunctive techniques and thus has good prospects. Depending on the stage, type, and location of skin cancer, various impedance‐based devices have been developed. These devices when used as an adjunct to visual methods have increased the sensitivity and specificity of skin cancer detection up to 100% and 87%, respectively, thus demonstrating their potential to minimize unnecessary biopsies. In this review, the authors track the advancements and progress made in this technique for the detection of skin cancer, focusing mainly on the advantages and limitations in the clinical setting. © 2022 Bioelectromagnetics Society.

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Millimeter-Wave Near-Field Probe Designed for High-Resolution Skin Cancer Diagnosis

Cited by 51 publications

References 35 publications

Optimization of Micromachined Millimeter-Wave Planar Silicon Lens Antennas With Concentric and Shifted Matching Regions

Optimization of Micromachined Millimeter-Wave Planar Silicon Lens Antennas With Concentric and Shifted Matching Regions

Advances in Microwave Near-Field Imaging: Prototypes, Systems, and Applications

Adjunctive Diagnostic Methods for Skin Cancer Detection: A Review of Electrical Impedance‐Based Techniques

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