Broadband conical beam antenna in planar environment

Abstract

In this article, a substrate‐truncated microstrip circular patch antenna with shorting vias is proposed for X‐band applications. The bandwidth of the designed antenna is substantially increased by making two slots—one circular and another annular ring—at the top of the structure which actually helps in bringing two individual resonating frequencies closer to each other. The antenna is simulated using the Ansoft HFSS, and various parameters are optimized for better performance. The deigned structure is finally fabricated and tested, and the measured data fairly agree with the simulated results. The measured relative impedance bandwidth (|S11| < −10 dB) is found to be 28.5% (8.9‐11.85 GHz). The proposed antenna is behaving like a monopole with the radiated beam of conical shaped in the entire operating band having a maximum gain of 7.2 dBi.

Deep Learning-Based Three-Dimensional Oral Conical Beam Computed Tomography for Diagnosis

“…At this time, the two-dimensional output needs to be input into the normalized exponential function (Softmax) to get the probability of the current image corresponding to each class and then calculate the loss by combining the loss function. The loss function adopted by DDOM in the first stage of training is the cross-entropy loss function, and the specific calculation formula of the loss is shown as follows: where y i represents the actual marking category of the current sample X i , y i =1 represents the current sample X i , and it belongs to class j ; represents the output obtained after the current sample X i is input to the network, and it is a two-dimensional vector; represents the output of the current sample X i corresponding to class j ; and C represents the total number of categories [ 15 , 16 ]. Since the first stage is divided into diseased images and normal images, C = 2.…”

“…where y i represents the actual marking category of the current sample X i , y i � 1 represents the current sample X i , and it belongs to class j; Y i represents the output obtained after the current sample X i is input to the network, and it is a two-dimensional vector; Y i [j] represents the output of the current sample X i corresponding to class j; and C represents the total number of categories [15,16]. Since the first stage is divided into diseased images and normal images, C � 2. e following gradient return formula (2) can be obtained according to the cross lineal loss function in the first stage:…”

A wideband monopolar patch antenna with a high system fidelity factor for IR‐UWB application

“…To realize the wideband pattern stability and compact size, some common methods are to control the frequencies of the fundamental $${\text{TM}}_{01}$$ and $${\text{TM}}_{02}$$ modes to be close to each other 6 and have a higher profile 12 . Based on the above methods, a matching technique for two separate modes with a certain frequency gap is further discussed in our design.…”

“…Various techniques have been reported to achieve much larger bandwidth than conventional designs, including adding shorted metal vias, 6–8 coupling rings, 5,9,10 etching slots, 11,12 and using coupled‐fed technology 13,14 . In 2013, Liu proposed a method to control the frequencies of the $${\text{TM}}_{01}$$ and $${\text{TM}}_{02}$$ modes to achieve an impedance bandwidth of 18% 6 .…”

“…Consequently, the improving matching technique for $${\text{TM}}_{\text{0n}}$$ modes with a slightly higher profile has gained attention. Two ring slots are etched on a circular patch in Prasad et al 12 to obtain the capacity gap which obtains an impedance bandwidth of 28.5%. The circular antenna with a coupled annular ring is coupled‐fed by a T‐shape probe, 14 broadening the bandwidth to 55.3%.…”