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Article
A New Topology of Load Network for Class F RF Power Amplifiers

Author: Firas Mohammed Ali Al-Raie
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2016 Volume: 34 Issue: 11 Part (A) Engineering Pages: 1944-1958
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

High efficiency RF power amplifiers are increasingly needed in modern mobile communication systems to reduce the battery size and power supply consumption. Class-F RF power amplifiers offer improved efficiency over the conventional class-B power amplifiers by properly controlling the harmonic components of the voltage and current signals at the output terminals of the RF device while driving it to operate as an ON/OFF switch. To do this task, a suitable load network is to be synthesized in order to present the proper harmonic impedances at the output of the RF power transistor. In this paper, a new load network for class F power amplifiers has been introduced and derived analytically. The proposed network consists of a parallel short circuited λ/8 stub, parallel open circuited λ/8 stub, and a T-section lumped-elementtransformer. The benefits of this topology include simplicity of design, controllable bandwidth, and harmonic tuning and impedance transformation at the same time.To confirm the approach of analysis, a 10 W class-F UHF power amplifier circuit has been designed and simulated using a typical Gallium Nitride high electron mobility RF transistor (GaN HEMT) to operate at 500 MHz with the aid of the Advanced Design System (ADS)computer package. The simulated results haveindicated that the circuit gives adc-to-RF efficiency of more than 84 % and a power gain of 11 dB at 500 MHz with an operating bandwidth from 440 to 540 MHz.


Article
Breast Cancer Detection Using Photoacoustic Imaging
الكشف عن سرطان الثدي باستخدام التصوير الضوئي- الصوتي

Author: Luma W. Jameel لمى وليد جميل
Journal: Al-Nisour Journal for Medical Sciences مجلة النسور للعلوم الطبية ISSN: 26640562 26640554 Year: 2019 Volume: 1 Issue: 2 Pages: 195-212
Publisher: Al-Nisour University College كلية النسور الجامعة

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Abstract

This work is about a tumor detection using photoacoustic technique, the photoacoustic waves generation and detection in tissue phantom (liver in chicken breast) which used to representing the real tissue. The one dimensional photoacoustic signal was generated using Nd:YAG laser, detected using piezoelectric detector and displayed on a storage oscilloscope, the experimental work is done at Different depth, thickness and the distance to the detector for several phantoms and different laser energy 250,400 and 500 mJ.

هذا البحث للكشف عن الاورام باستخدام تقنية التصوير الضوئي الصوتي، ان توليد الموجه الضوئية الصوتية وكشف عنها في الخلية باستخدام نسيج تجريبي يستخدم لتمثيل الخلايا الحقيقة.الاشارة احادية البعد تولدة باستخدام Nd:YAG ليزر وتكشف باستخدام كاشف البيزو وتعرض باستخدام عارض الموجات، التجربة العملية تمت باستخدام عمق وعرض ومسافة مختلفة وطاقات مختلفة.

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