Peyman Mahouti

Efficient scattering parameter modeling of a microwave transistor using Generalized Regression Neural Network

In this paper, a simple, accurate, fast and reliable black-box modeling is presented for the Scattering (S-) parameters of a microwave transistor from the reduced amount of the discrete data using General Regression Neural Network (GRNN). GRNN is a probability- based Neural Network and has been used in the generalization applications in the cases of the existence of the poor data bases. In this work, the GRNN-based modeling is implemented to the microwave transistor BFP640 with the separate interpolation and extrapolation applications and the comparative results are given. It can be concluded that the superior extrapolation ability of a GRNN can be used in generalization of the reduced amount of scattering parameter data accurately to the entire operation domain of device, thus in S- parameter modeling of a microwave transistor can be achieved.

Honey- bees mating algorithm applied to feasible design target space for a wide- band front- end amplifier

In this article, the feasible design target space is determined for the input stage-requirements of an ultra-wide band low-noise front end design using a single transistor. The problem is set as an optimization problem where honey-bees mating have been used as search and optimization tool within in the problem domain. The primary reason to use this algorithm is ease of its use, broad applicability and global perspective. The honey-bee mating process has been considered as a typical swarm-based approach to optimization, in which the search algorithm is inspired by the process of honey-bee mating in real life. In this paper, the honey-bee mating (HBMO) algorithm is presented as a new meta-heuristic optimizationtool to determine design target space for a microwave amplifier subject to the potential performance of the employed transistor.

Microstrip SIW patch antenna design for X Band Application

In this paper, designs of both circular and octagonal microstrip patch antennas are presented on the Substrate Integrated Waveguide (SIW) for X- Band Applications. Both antennas are modelled and simulated using the full -wave simulator CST MWS. It can be concluded that the proposed antenna designs are able to achieve high gain and directivity with the miniature, compact, light, cost effective and easy to fabricate structures.

Frequency-selective surfaces to enhance performance of TEM horn antenna

This article presents the analysis and investigation of the effect of loading a TEM horn antenna with a frequency selective surface (FSS) of finite size. It is simulated on FR4 (lossy) of relative permittivity 4.4, thickness 1.58mm and loss tangent 0.0035. This structure is called a filtering antenna (filtenna). Basically it is applied for filtering and minimizing the interference and noise in the desired band. The filtration is carried out using a finite FSS of double square loop of overall dimensions 20mm×20mm. The structure is simulated using CST MWS.

An UWB Vivaldi antenna with the enhanced functionalities through the use of DGS and dielectric lens

Nowadays UWB antennae have become popular due to the growing need for both the UWB ground and space communication. In this work, an UWB Vivaldi antenna is proposed with the enhanced functionalities through the use of DGS and dielectric lens for to be used for both ground and space communications. Performance enhancement of an UWB Vivaldi antenna is worked out on Roger 4350B substrate (єr=3.66, tanô=0.038, h= 1.58mm) within the bandwidth of 1–14 GHz using the CST Microwave Studio environment. For the purpose, Defected Ground Structure (DGS) and dielectric lens are used in the low and high frequency regions, respectively. In this work, Vivaldi antenna structure is particularly preferred due to its cost-effective and simple manufacturing over 1 GHz. Furthermore, performance enhancement of the antenna also verified experimentally as compared with the simulated return loss and radiation gain characteristics within the 1–14 GHz bandwidth.

Design and manufactering of an X-band horn antenna using 3-D printing technology

Herein, design and manufacturing of an X-band pyramid horn antenna using 3-D printer is studied with its experimental results. X-band is used for the military purposes with the marine and satellite technology based on the geographic discovery. Horn antennas are especially very preferable in these applications since they can be built easily at the different types depending on their utilizations and provide low voltage standing wave ratios. This work is focused on a pyramid horn antenna design and its manufacturing method with 3-D printer technology. The measurement results of the 3-D printed antenna are also compared with the simulation results.

Microstrip frequency selective surface for use in horn Filtenna

This work presents design of Microstrip Frequency Selective Surface (MFSS)s to be fixed into the apertures of horn antennas for pre-filtering unwanted signals at 4GHz, 9 GHz. Thus integration of the antenna and band-pass filter is achieved into a single module so that a pre-filtering process can be carried out when signal is received by the antenna that makes the entire system be more compact and improves its performance. Furthermore since MFSS s consist of simply identical microstrip patch arrays, this constitutes a feasible solution especially when the unwanted signals are exceptionally strong compared to the desired in-band signals, which make required front-end RF filter performance be more rigorous. All the designs and analysis have been completed by the full-wave EM simulator CST using low-cost FR4 with the relative permittivity 4.4, thickness 1.58mm, loss tangent 0.0035 starting from the unit element. The paper briefly reviews the design and simulation stages compared to the measurements made by our research group and published in [8], [9] and [10]. From the measured results within 4GHz-9GHz bandwidth, it can be found that the proposed modules keep return loss characteristics of the horn antennas, meanwhile enhancing gain and beam width to effectively attenuate interference and noise signals at the out-band. Besides, this methodology implemented to design horn Filtennas to filter GSM signals at 1800 MHz for radar application. All the horn Filtennas will be presented in details in the workshop.

Design of Dielectric Lens Loaded Double Ridged Horn Antenna for Millimetre Wave Application

In this paper, designs of Dielectric Lens Loaded Double Ridged Horn Antenna for Millimetre Wave Applications is investigated. Firstly a double ridged horn antenna is designed and simulated in CST environment. After that, 2 dielectric lens architecture are designed and placed at the aperture of the antenna. It is seen that by placing spherical shaped dielectric lens, it is possible to achieve improvement in return loss and farfield gain of the antennas design in a 20–40 GHz bandwidth.

Coplanar stripline-fed Microstrip Yagi-Uda antenna for ISM band application

In this paper, design and experimental results of a coplanar stripline fed Microstrip Yagi-Uda antenna are presented. The proposed antenna consists of a microstrip line to coplanar stripline transition, reflector microstrip patch, coplanar stripline-fed driver dipole, and three director microstrip patches on low-cost FR4 with the relative permittivity 4.4, thickness 1.58mm, loss tangent 0.025. The 10-dB bandwidth and gain are measured as 130 MHz at the center frequency of 2.45 GHz, 7.5 dBi.

Design and realization of dual band Microstrip Monopole antenna

Herein, design and experimental results of a dual band Microstrip Monopole antenna are presented. The proposed antenna consists of a zig-zag microstrip line as monopole patch alongside of a Defected Ground structure under the fed-line of the antenna for size miniaturization propose, fabricated on FR4. The 10-dB bandwidth and gain performances are measured as 130 MHz and 6 dB at the centre frequency of 2.42 GHz, and140 MHz, and 2dB at the centre frequency of 5.92 GHz respectively.