A New Design of an UWB Circular Fractal Printed Antenna

A Microstrip Antenna (MSA) has been computed and analysed in this study by using CST of Microwave studio as Electromagnetic solver by generating the coefficient of reflection, the Gain, the density of current and the radiation pattern in the frequency range 3.1-10.6 GHz which commercialised by the Federal communication commission (FCC) as an Ultra-wide band (UWB) frequency range. The substrate used to achieve the proposed structure is the FR4-Epoxy with a thickness of 1.6 mm, a constant dielectric of 4.4 and a loss tangent of 0.025. The radiating patch is a circular shape etched with different sizes to create the fractal geometry. The transmission line has been designed by including a tapered section in the part connected to the radiator. The design of the antenna has been verified by using ADS and CST solvers. The fabrication of the antenna has been performed in order to measure the coefficient of reflection and the radiation pattern

A new design of a low cost multiband fractal CPW-fed antenna

This paper presents a new design of the fractal multiband antenna structure. The proposed antenna is optimized by using CST-MW studio, this structure is a CPW-Fed antenna which makes it easier to integrate with RF devices. The final validated circuit is designed to operate in the Industrial Scientific and Medical (ISM 2.4 – 2.5GHz), worldwide interoperability for microwave access (WiMAX 3.30 – 3.80 GHz), IMT advanced system (3.40 – 4.20 GHz). The properties of antennas, for example, yield loss, radiation patterns and gain are determined by numerical simulation and measurement

Compact Photonic Transmitter Based on Annular Ring Antenna for THz Applications

This paper presents the design of Continuous Wave Terahetz photonic transmitters based on photodector which convert the light signal to electrical signal, THz antenna, low-pass filter (LPF) and DC Probe. In the design of the CW THz photonic transmitter System, we begin with the matching input impedance and validation of THz antenna using an EM solver Momentum integrated in ADS “Advanced Design System”. Then we pass to the optimization of a low-pass filter which had the role of inductance, blocking the RF signal providing from the antenna to reach the DC probe. Finally, we associate the previous structures with a DC probe and simulate the whole circuit until validating the CW THz photonic transmitter circuit. The three structures are based on multi-layers GaAs substrate, which is the most widely used for THz circuit design. The dimensions of the whole circuit are 819.071 × 164.10 2

1.25 GHz – 3.3 GHz broadband solid state power amplifier for L and S bands applications

The research of a single stage broadband solid-state power amplifier based on ATF13876 transistor, which operates in the frequency ranging from 1.25 GHz ~3.3 GHz is presented in this paper. To achieve the broadband performance of the operating bandwidth, a multi-section quarter wave impedance transformer and an approximate transformation of previously synthesized lumped elements into transmission lines are adopted. With neatly design of broadband matching networks and biasing circuit, excellent matching performances and unconditionally stability are achieved over the whole operating bandwidth with a maximum gain of 17.2 dB. The large signal simulation shows that the proposed circuit reaches a saturated output power of 18.12 dBm with a maximum PAE of 27.55% and a 1-dB compression point at 5 dBm input power level. Considering the wide frequency coverage, the features of the proposed design compares favorably with the contemporary state-of-the-art

A Miniature Microstrip Antenna Array using Circular Shaped Dumbbell for ISM Band Applications

The aim of this work is the achievement, and the validation of a small microstrip patch antenna array using a circular shaped dumbbell defected ground structure. This work has been dividing into two stages: The first step is to miniaturize a microstrip patch antenna resonating at 5.8GHz, which operate in the Industrial Scientific Medical band (ISM) and the second is to use a circular defected ground structure to shift the resonance frequency of the antenna array from 5.8GHz to 2.45GHz. At last, a miniaturization up to 74.47%, relative to the original microstrip antenna array has accomplished. The antenna structure has designed, optimized and miniaturized using CST MW Studio. The obtained results have compared with Ansoft’s HFSS electromagnetic solver. The antenna array has fabricated on FR-4 substrate, and its reflection coefficient is measured

A novel compact CPW tunable stop band filter using a new Z-DGS-resonator for microwave applications

The paper presents a novel very compact CPW bandstop filter. The designed structure consists of one unit of new Z-DGS resonator, placed on top layer of ground plane between the input and output this structure, which is excited by 50 ohm coplanar line. The designed filter can be used in X-Band applications as the band stop can be shifted to any other desired frequency by tuning the length of the Z-DGS. The proposed filter topology has as benefits good performances in terms of wide stop-band rejection, low insertion loss, high return loss, simple design and more small size (17.908 × 10 mm2) compared to other previous works those reported in literature. The stop-band width is from 3.96GHz to 6.21GHz, exhibits a 22,25 dB rejection bandwidth of 45% with high selectivity characteristic at the center frequency of 5.05 GHz

Design of Negative Resistance Oscillator with Rocord Low Phase Noise

The aim of this paper is to use a new design of a negative resistance microwave oscillator in order to fabricate oscillator with very good performance in terms of output power, efficiency, stability and phase noise. In this study the new concept of oscillator using distributed resonator and micro-strip circuit elements improve performances of our structure. A micro-strip microwave oscillator with low phase noise based on an NPN silicon planar epitaxial transistor has been designed, fabricated, and characterized. In this design, each step has been conducted by using Advanced Design System (ADS) and following a theoretical study which enable to optimize the different performances of the whole circuit. The oscillator produce a sinusoidal signal with spectrum power of 12.25 dBm at 2.45 GHz into 50 Ω load when polarized at Vcc=15V with DC to RF efficiency of 16. The obtained phase noise of -120 dBc/Hz at 100 Hz offset is the result of the use of high Q factor resonator and the depth study of the parameters of the oscillator. Simulation and measurement results are in good agreement

A Novel Design of a Microstrip Microwave Power Amplifier for DCS Application using Collector-Feedback Bias

This paper presents a 1.80GHz class-A Microwave power amplifier (PA). The proposed power amplifier is designed with single-stage architecture. This power amplifier consists of a bipolar transistor and improved by Collector-Feedback Biasing fed with a single power supply. The aim of this work is to improve the performance of this amplifier by using simple stubs with 50Ω microstrip transmissions lines. The proposed PA is investigated and optimized by utilizing Advanced Design System (ADS) software. The simulation results show that the amplifier achieves a high power gain of 13dB, output power rise up to 21dBm and good impedances matching ;For the input reflection coefficient (S11) is below than - 46.39dB. Regarding the output reflection coefficient (S22) is below than -29.898dB, with an overall size of about 93 x 59mm². By the end; we find that this power amplifier offers an excellent performance for DCS applications

A Two-stages Microstrip Power Amplifier for WiMAX Applications

Amplification is one of the most basic and prevalent microwave analog circuit functions. Wherefore power amplifiers are the most important parts of electronic circuits. This is why the designing of power amplifiers is crucial in analog circuit designing. The intent of this work is to present an analysis and design of a microwave broadband power amplifier by using two stages topology. A two stages power amplifier using a distributed matching network for WiMAX applications is based on ATF-21170 (GaAs FET). The configuration aims to achieve high power gain amplifier with low return loss over a broad bandwidth. The proposed BPA is designed with a planar structure on an epoxy (FR4) substrate. The planar structure is also utilized for getting the good matching condition. The advanced design system (ADS) software is used for design, simulation, and optimization the proposed amplifier. The complete amplifier achieves an excellent power gain; is changed between 28.5 and 20dB with an output power of 12.45dBm at 1dB compression point. For the input reflection coefficient (S11) is varied between -20 and -42dB. While the output reflection coefficient (S22) is varied between -10 and - 49dB over the wide frequency band of 3.2-3.8GHz

A Novel Configuration of A Microstrip Power Amplifier based on GaAs-FET for ISM Applications

Power Amplifiers (PA) are very indispensable components in the design of numerous types of communication transmitters employed in microwave technology. The methodology is exemplified through the design of a 2.45GHz microwave power Amplifier (PA) for the industrial, scientific and medical (ISM) applications using microstrip technology. The main design target is to get a maximum power gain while simultaneously achieving a maximum output power through presenting the optimum impedance which is characteristically carried out per adding a matching circuit between the source and the input of the power amplifier and between the load and the output of the power amplifier. A "T" matching technique is used at the input and the output sides of transistor for assure in band desired that this circuit without reflections and to obtain a maximum power gain. The proposed power amplifier for microwave ISM applications is designed, simulated and optimized by employing Advanced Design System (ADS) software by Agilent. The PA shows good performances in terms of return loss, output power, power gain and stability; the circuit has an input return loss of -38dB and an output return loss of -33.5dB. The 1-dB compression point is 8.69dBm and power gain of the PA is 19.4dBm. The Rollet's Stability measure B1 and the stability factor K of the amplifier is greater than 0 and 1 respectively, which shows that the circuit is unconditionally stable. The total chip size of the PA is 73.5× 36 mm2