Isolator & Circulator -FT.pptx
- 1. ISOLATORS AND CIRCULATORS - APPLICATION IN EM WAVE TRANSMISSION FIELD THEORY
- 2. CIRCULATORS AND ISOLATORS • Both microwave circulators and microwave isolators are nonreciprocal transmission devices that use the property of Faraday rotation in the ferrite material. • To understand the operating principles of circulators and isolators, let us describe the behavior of ferrites in the nonreciprocal phase shifter.
- 3. ISOLATOR • An isolator is a nonreciprocal transmission device that is used to isolate one component from reflections of other components in the transmission line. • An ideal isolator completely absorbs the power for propagation in one direction and provides lossless transmission in the opposite direction. • Thus the isolator is usually called uniline.
- 4. ISOLATOR • Isolators are generally used to improve the frequency stability of microwave generators, such as klystrons and magnetrons, in which the reflection from the load affects the generating frequency. • In such cases, the isolator placed between the generator and load prevents the reflected power from the unmatched load from returning to the generator. • As a result, the isolator maintains the frequency stability of the generator.
- 5. • Isolators can be made by inserting a ferrite rod along the axis of a rectangular waveguide as shown in aboveFigure. • The input resistive card is in the y-z plane, and the output resistive card is displaced 45° with respect to the input card. The dc magnetic field, which is applied longitudinally to the ferrite rod, rotates the wave plane of polarization by 45°. • The degrees of rotation depend on the length and diameter of the rod and on the applied dc magnetic field. • An input TE10 dominant mode is incident to the left end of the isolator. Since the TE10 mode wave is perpendicular to the input resistive card,the wave passes through the ferrite rod without attenuation.
- 6. ISOLATOR • The wave in the ferrite rod section is rotated clockwise by 45° and is normal to the output resistive card. As a result of rotation, the wave arrives at the output end without attenuation at all. • On the contrary, a reflected wave from the output end is similarlyrotated • clockwise 45° by the ferrite rod. However, since the reflected wave is parallel to the input resistive card, thewave is thereby absorbed by the input card. • The typical performance of these isolators is about 1-dB insertion loss in forward transmission and about 20- to 30-dB isolation in reverse attenuation.
- 7. CIRCULATOR • It is a multi-port microwave passive device. •It is a non-reciprocal device. •The wave can travel from one part to the next immediate port in one direction only’ •TYPES: Three port Circulator Four port Circulator Micro strip Circulator
- 8. THREE PORT CIRCULATOR ● 3-Port circulator is formed by a 120 degree H-planes waveguide. (or) Strip line Symmentrical y-junction with a control ferrite post ● Depending on the polarization of incident wave and the direction of ‘H the microwave signal travels from one port to another.
- 9. FOUR PORT CIRCULATOR •Two magic – Tees and a non-reciprocal 180 degree phase shifter. •A combination of two 3 dB directional couplers with two non-reciprocal phase shifter. •A signal at port 2 will be split into two eqaual amplitude and in-phase waves in the collinear arms ‘a’ and ‘d’ of Magic Tee 2. •Due to presence of the non-linear 180 degree phase shifter , the waves appeared at ‘b’ and ‘c’ are out of phase. •These waves add up and appear at port 3 as an output.
- 10. FOUR PORT CIRCULATOR • Many types of microwave circulators are in use today. However, their principles of operation remain the same. • A perfectly matched, lossless, and nonreciprocal four-port circulator has an S matrix of the form Using the properties of S parameters as described previously, the S matrix in Eq.
- 12. Electromagnetic Waves • If you have ever tuned in to listen to a radio ,a spoken headphone , turned on a light ,hand on X ray taken, felt the warmth of the sun on your skin. • You have experienced ELECTROMAGNETIC WAVE. • “Electromagnetic waves are waves which can travel through the vacuum of outer space . • Electromagnetic waves are formed when an electric field couples with a magnetic field. • The magnetic and electric fields of an electromagnetic waves are perpendicular to each other and to the direction of waves.”
- 13. Production of ElectromagneticWaves • When an electric charge vibrates, the electric field around it changes creating a changing magnetic field. • The magnetic and electric fields create each other again and again. • An EM wave travels in all directions. The figure only shows a wave traveling in one direction. • The electric and magnetic fields vibrate at right angles to the direction the wave travels so it is a transverse wave
- 14. Propertiesofelectromagnetic wave 1. All are electromagnetic waves are transverse 2. They do not required any medium to travel though . 3. They travel at speed of 3 multiple by 10 -8 in vacuum. 4. They can all be reflected and refracted. 5. They can all be emitted and absorb by matter.
- 15. ElectroSpectrum “Frequencies is called the electromagnetic spectrum. ”Differentpartsinteractswithmatterin differentway. As wavelength decreases, frequency increases… • The ones humans can see are called visible light, a small part of the whole spectrum. • Includesfollowingtypesofwaves: Radiowaves, Microwaves,Infraredwaves,Visiblelight,Ultraviolet, X rays,Gammarays
- 16. RADIO WAVES • Radiowaveshavethelongest wavelengthsofallthe electromagnetic waves. • Lowfrequency. • Radio waves are often used to transmit data and have been used for all sorts of applications includingradio,satellites,radar, andcomputernetworks. Inmedicines: • Is used to produce images of soft tissues, fluid, fat and bone. • Example : MRI and RFA.
- 17. MICRO WAVES • Microwaves are useful in communication because they can penetrate clouds, smoke, and light rain. • Microwave also in radar that helps to predict the weather. Inmedicines: • Microwaves are useful in communication because they can penetrate clouds, smoke, and light rain. • Microwave also in radar that helps to predict the weather. • Microwave ablation: used in treatment of liver tumor • Microwave diathermy: used in pain management
- 18. INFRARED WAVES • Infrared waves are sometimes classified as "near" infrared or "far" infrared • Between microwaves and visible light are infrared waves. • Can be detected by heat and used in heat lamp. • Higher energy then microwave and lower the visible light. • Used daily in remote controls, to read CD-ROMs
- 19. Infrared Imaging in Medicine • Oncology • Vascular disorders • Respiratory disorders • Skeletal • neuromuscular diseases • Surgery • Tissue viability
- 20. Visiblelight • This is the range of wavelengths from 390 to 700 nm which corresponds to the frequencies 430-790 THz. • The portion of the electromagnetic spectrum that human eyes can detect. Inmedicines: • Visible light is also used in Scanning laser ophthalmoscope. • In Endoscopy/ Keyhole Surgery
- 21. ULTRA VIOLET WAVES • Ultraviolet waves have the next shortest wavelength after visible light. • EM waves with wavelengths from about 400 billionths to 10 billionths of a meter. • Used in tanning beds and sterilizing equipments. Inmedicines: • Have enough energy to enter skin cells • Longer wavelengths – UVA • Shorter wavelengths – UVB rays • Both can cause skin cancer
- 22. XRays • High wave energy • Used in : Medicines Industry Transportation • To much exposure can damage the living tissue or even cause cancer Inmedicines: • X-rays play an important role in dentistry and orthopedic investigation. • They can penetrate soft tissue like skin and muscle. • Are used to take X-ray pictures of bones in medicine.
- 23. GAMMA RAYS • Gamma rays the highest energy electromagnetic waves • The actually come from radioactive elements or stars • Inspection tools in industry Inmedicines: Positron Emission Tomography (PET) is a nuclear medical imaging tool which used gamma rays. • Example : • Neurological diseases such as Alzheimer’s and Multiple Sclerosis • Effectiveness of treatments
- 24. CREDITS: This presentation template was created by Slidesgo, and includes icons by Flaticon, and infographics & images by Freepik Thankyou! Please keep this slide for attribution PRESENTED BY; Keerthika T Kunguma Nandhitha S Madhankumar S Malarvizhi M Manoj K