Microwave imaging is an efficient technique that can be used for the early detection of breast cancer. Therefore the current research article presents the microwave imaging of two spherical tumors (radius 4 and 5 mm) in the breast phantom by using the monostatic radar-based technique. This is carried out by using an ultra-wideband (4.9–10.9 GHz), three-layered stacked aperture coupled microstrip antenna (SACMPA) with a defected ground structure to scan the breast phantom and make near field S parameter measurements from a breast phantom. The S parameter data from different locations and at different time intervals are noted and then used in a beam-forming algorithm; Delay and Sum to process it and form a 2D image of the tumor location in the breast phantom using MATLAB. The proposed SACMPA is a three-layered structure with overall dimensions of 37 × 43 × 4.85 mm3 that shows an impedance bandwidth of 6 GHz (4.9–10.9 GHz) and a simulated peak gain of 6.32 dB at a frequency of 9.1 GHz. The validation of S parameters and gain results are done using a Vector Network Analyzer (VNA) and an anechoic chamber. The experimental validation of the proposed microwave imaging procedure is done by allowing the SACMPA to radiate parallel to the breast phantom made from polythene (skin), petroleum jelly (fat), and wheat flour (with water as tumor) and record the S parameters on the VNA. The proposed microwave method is safe for human exposure as the antenna also shows simulated specific absorption rates of 0.271 and 1.115 W/Kg (on the breast phantom) at frequencies of 5.7 and 6.5 GHz, respectively (for 1 g of body tissue).

This research article presents a proficient, convenient, and low-cost monostatic radar-based microwave imaging (RBMI) technique for the breast tumor detection. For this, a compact cubical dielectric resonator antenna (DRA) with impedance bandwidth of 8.3 GHz (ie, 4.3-12.6 GHz) has been simulated using CST V 0 17. In proposed monostatic RBMI technique, the designed DRA is placed parallel to the breast phantom and rotated around it at an interval of 10 in elevation plane (0-π) and azimuthal plane (0-2π), respectively; first, without and then with tumor inside the breast phantom. Total 1080 back-scattered signals are recorded for the entire impedance bandwidth, and processed for microwave imaging. For the validation of results, fabricated antenna is rotated around the artificial breast mimic. The artificial breast mimic is made up from gelatin (skin), petroleum jelly (fat), and wheat flour (tumor). The backscattered signals from the artificial breast phantom have been recorded on the vector network analyzer model no. E5063A for both the cases that is, with absence and presence of tumor at different position and time intervals. The recorded S-parameters have been processed in two beam-forming algorithms; delay and sum (DAS), delay multiply and sum (DMAS). These signals are then converted into digital data and processed in the MATLAB, to visualize the 2D image of the scanned area to detect the breast tumor. By comparing the reconstructed images, it is concluded that the DAS algorithm provides just a clue about the presence of the tumor, but DMAS provides the accurate position and size of the breast tumor.

The inherent advantages of microwave imagining (MWI) being noninvasive and nonionizing for cancer detection, has attracted the attention of researchers in this area. Therefore, the present research article proposes an UWB (ultrawideband) stacked MSA (Micro-strip antenna) for MWI of skin cancer. The proposed research work precisely focuses on the diagnosis of skin cancer in human forearm using the designed MSA in mono-static radar based configuration to collect S parameter data and process it to form an image of the scanned body area. The proposed UWB SAMPA (stacked aperture coupled micro-strip patch antenna) has three layered stacked aperture coupled geometry with a defected ground structure with dimensions 36 Â 30 Â 4.85 mm 3 . A simulated and measured bandwidth of 6.23 GHz (6.14 to 12.37 GHz) and 5.28 GHz (5.72 to 11 GHz) are observed and a gain of 6.3 and 6.4 dB is reported respectively.The in vitro detection of skin cancer is done by fabricating a bio mimic of human forearm with same electrical properties as that of human skin. The proposed SAMPA is used to collect S parameter data from the scan of forearm phantom. This data is then processed in beamforming algorithms to create a 2D dielectric profile of the scanned forearm area. The multiply Delay and Sum with Coherent factor (CF-DMAS) beam forming algorithm is utilized for reconstruction of the 2D image of the cancerous effected area along with its locations and size in MATLAB. The proposed MWI procedure is validated experimentally with the prototype of proposed SAMPA and a human forearm phantom after simulations in CST MWS. The proposed SAMPA is also safe for the human exposure, as it has simulated specific absorption rate (SAR) on the forearm phantom of 1.013 and 1.09 at frequency 7.04 and 8.67 GHz respectively. K E Y W O R D Smicrowave imaging, multiply delay and sum with coherent factor, skin cancer, stacked aperture coupled micro strip antenna

An aperture coupled stacked Sierpinski gasket fractal antenna with a defected ground structure is proposed in the current article for ultra wide band (UWB) and wireless local area network (WLAN) applications. The radiating structure is formed of two Sierpinski gasket fractal patch antenna layers on two layers of FR4 substrate stacked one over the other. This stacked structure is fed by a third (bottom) layer also of FR4 substrate, with ground layer at its top and the feed line with a stub, at the bottom. The top ground layer has a ‘†’ shaped slot cut in it to provide a wideband behavior to the antenna, and the feed line is designed with a stub to provide circular polarization to the EM fields radiated by the proposed antenna. The antenna is designed using CST Microwave Studio version 2010 assuming perfect boundary conditions. The proposed antenna shows a dual band wideband behavior with an impedance bandwidth of 630 MHz (4.75–5.38 GHz) and 400 MHz (6.8–7.2 GHz) with a gain of 5.85 dB and 9.5 dB at the center frequencies of the two bands, respectively. The antenna is capable of covering two UWB bands from (4.75–5.28) GHz and (6.8–7.2) GHz, a radio astronomy band from (5.01–5.03) GHz and IEEE 802.11a band from (5.15–5.35) GHz. The prototype of the proposed antenna is tested using a VNA and an anechoic chamber to validate against the simulated results. The proposed antenna has volumetric dimensions of 6 × 6 × 0.483 cm3 which makes it a suitable choice for RF front end circuits. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2786–2792, 2015

This article presents the design, development, and experimental validation of an aperture coupled complementary Sierpinski gasket equilateral triangular fractal antenna array for portable 4G/5G UWB communication devices. The proposed antenna array is printed on two FR-4 substrate layers (ε r = 4.4, height = 1.57 mm, and tan δ = 0.024) with two fractal triangular patches on the top layer (separated by a distance of 3λ/2) and feed network on the bottom layer of FR-4. The fractal patches (optimized up to second order of iteration) are fed using an aperture-coupled feeding mechanism, where the aperture slots in the ground layer are modified to complementary Archimedean spiral slots which are interconnected by a modified "X" shaped slot to improve the impedance matching at the operational bands. The proposed array has overall volumetric dimensions of 41 × 99.4 × 3.245 mm 3 and provides a size reduction of 46% for the metallic area using the fractal geometry. The proposed array shows a simulated UWB response from 4.3 to 11.6 GHz (fractional bandwidth of 91.8% at 7.95 GHz) with a simulated peak gain of 4.7 dB (at 9.2 GHz) and port-to-port isolation of ≤−15.8 dB for the entire band. For validation of simulated responses, the proposed array is fabricated and tested for S-parameters (S 11 , S 22, S 12 , and S 21 ). A measured impedance bandwidth of 6.3 GHz is observed for a frequency band from 5.7 to 12 GHz. Two additional frequency bands are also exhibited by the array from 4.1 to 4.25 GHz and 4.7 to 5.3 GHz. The array diversity parameters such as envelope correlation coefficient (≤0.007 [simulated], ≤0.0057 [measured]), diversity gain (≥9.999 [simulated], ≥9.971 [measured]), mean effective gain (≥−3.9 dB [simulated], ≥−5.1 dB [measured]), and channel capacity loss, (≤0.37 bits/s/Hz [simulated], ≤0.4 bits/s/ Hz [measured]) which are calculated using the simulated and measured S-parameters of the array are also observed. These parameters allow the proposed fractal array to be implemented in a diversity combining technique to improve the overall SNR and hence support a high data rate for 4G/5G multimedia services. K E Y W O R D S aperture coupled feed, complementary Archimedean spiral, complementary Sierpinski gasket fractal, multiple-input multiple-output (MIMO), UWB