antenna ppt basic antenna and its working

antenna

1. TYPES OF ANTENNAS AND ITS APPLICATIONS Presented by Dr.A.PramodKumar. M.Te ch ,Ph.D . Assistant Professor Department of ECE Vardhaman College of Engineering

2. Micro-strip Antennas In its most basic form, a Microstrip patch antenna consists of a radiating patch on one side of a dielectric substrate which has a ground plane on the other side For good antenna performance, a thick dielectric substrate having a low dielectric constant is desirable since this provides better efficiency, larger bandwidth and better radiation . In ge n ar a l M i c ro strip an t en n as are a l so known as “ PRINTED ANTENNAS ”. These are mostly used at microwave frequencies. Because the size of the antenna is directly t i e d the w av e l e n g th a t the resona n t frequency. Micro strip patch antenna or patch antenna is a narrowband wide-beam antenna. Structure of a Microstrip Patch Antenna Department of ECE

3. Overview of Microstrip Antennas Common Shapes Rectangular Square Circular Elliptical Annular ring T riangu l ar Department of ECE

4. Substrates for MSA Substrate Dielectric Constant (ε r ) Loss tangent (tanδ) Cost Alumina 9.8 0.001 Very High FR4 (or) Glass Epoxy 4.4 0.02 Low Duroid / Arlon 2.2 0.0009 Very High Foam 1.05 0.0001 Low/ Medium Air 1 NA Department of ECE

5. Rectangular Microstrip Antenna (RMSA) Co-axial feed Side V i e w  r Ground plane h Top V i e w L W X Y x Department of ECE

6. RMSA: Resonance Frequency where m and n are orthogonal modes of excitation. Fundamental mode is TM 10 mode, where m =1 and n = 0. L L e W e W x Department of ECE

7. RMSA: Design Equations BW α W and Gain α W Choose feed-point x between L /6 to L /4. Department of ECE

8. RMSA: Design Example Design a RMSA for Wi-Fi application (2.400 to 2.483 GHz) Choose Substrate: ε r = 4.4 , h = 1.6m m and tan δ = 0.02 = 3 x 10 11 / ( 2 x 2.4415 x 10 9 x √ 2.7 ) = 37 m m. W = 37 m m is taken = 4.119 L e = 3 x 10 1 1 / ( 2 x 2.4415 x 10 9 x √ 4.119 ) m m = 30.23 m m L = L e – 2 ∆L = 30.23 – 2 x 0.788 = 28.65 mm Department of ECE

9. Effect of Dielectric Constant ( ε r ) With decrease in ε r , both L and W increase, which increases fringing fields and aperture area, hence both BW and Gain increase. Department of ECE

10. Coaxial Feed A feed along the centerline at y = W /2 is the most common (minimizes higher-order modes and cross-pol). x y L W Feed at ( x , y ) Surface current x  r h z Feeding Methods Department of ECE

11. Adv a nt a g e s: Simple Directly compatible with coaxial cables Easy to obtain input match by adjusting feed position This type of feeding scheme is that the feed can be placed at any desired location inside the patch in order to match with its input impedance. Coaxial Feed x  r h z Feeding Methods x y L W  x , y  Department of ECE

12. Advantages : Simple F eed can be etched on the same substrate to provide a planar structure . Easy to use with arrays Easy to obtain input match In this type of feed technique, a conducting strip is connected directly to the edge of the micro strip patch. Feeding Methods Inset Feed Department of ECE

13. Advantages: Allows for planar feeding Less line radiation compared to microstrip feed Can allow for higher bandwidth (no probe inductance, so substrate can be thicker ) Two dielectric substrates are used such that the feed line is between the two substrates and the radiating patch is on top of the upper substrate. Feeding Methods Proximity-coupled Feed (Electromagnetically-coupled Feed) T o Top view M ic r ostr i p line Department of ECE Patch Micro strip line

14. Advantages: Allows for planar feeding Can allow for a match even with high edge impedances, where a notch might be too large (e.g., when using high permittivity) Microstrip line P a tch Gap Feeding Methods Gap-coupled Feed Patch Top view Microstrip line Department of ECE

15. Advantages: Allows for planar feeding Feed-line radiation is isolated from patch radiation Higher bandwidth is possible since probe inductance is eliminated (allowing for a thick substrate), and also a double-resonance can be created Allows for use of different substrates to optimize antenna and feed-circuit performance In this type of feed technique, the radiating patch and the micro strip feed line are separated by the ground plane . Coupling between the patch and the feed line is made through a slot or an aperture in the ground plane. P a tch Microstrip line Sl o t Feeding Methods Aperture-coupled Patch (ACP) Top view S lot Mic r o str ip line Department of ECE

16. Advantages Light weight, low volume, low profile, planar configuration, which can be made conformal Low fabrication cost and ease of mass production Linear and circular polarizations are possible Dual frequency antennas can be easily realized Feed lines and matching network can be easily integrated with antenna structure Department of ECE

17. Applications Pagers and mobile phones Doppler and other radars Satellite communication Radio altimeter Command guidance and telemetry in missiles Satellite navigation receiver Biomedical radiator Department of ECE

18. Department of ECE Reflector Antennas DR. RAFAEL ABRANTES PENCHEL − IWT 2015 Plane wavefront Spherical w a v e f r o n t

19. Introduction In Reflector antenna, another antenna need to excite it. Dipole Horn Slot used for excite so called primary antenna Reflector called as secondary antenna The operating principle of most reflector antennas is the same as lighthouse, lanterns, etc.: collimation of energy. The parabolic reflector antenna transforms an incoming plane wave into a spherical wave converging toward the focus . DR. RAFAEL ABRANTES PENCHEL − IWT 2015 Department of ECE

20. Reflector antennas are widely used to modify the radiation pattern of a radiating element. For example, the backward radiation from an antenna may be eliminated with a plane sheet reflector of large dimensions. In general, a beam of predetermined characteristics may be produced by means of a large, suitably shaped and illuminated reflector surface . Reflector antennas are widely used for high gain antennas . We can easily achieve above 30dB for microwave and higher frequencies. Department of ECE

21. Types of Reflectors Reflector represent any shape m ost common geometrics are Flat sheet reflector or Plane reflector Corner reflector Curved or parabolic reflectors Department of ECE

22. Department of ECE F lat sheet reflector or plane reflector Simplest form of reflector antenna i s kept infront of the feed Energy is radiated in the desired direction To increase the directivity, large flat sheet placed infront of the half dipole Main advantage is Reduce backward radiation and increase gain in forward direction

23. Department of ECE F lat sheet reflector or plane reflector

24. In fig (a) has a large flat sheet reflector near a linear dipole antenna to reduce backward radiation. Reflector element is backward insensitive to small frequency changes. The desirable properties of the sheet reflector may be largely preserved with the reflector reduced in size as in fig (b). In fig(c), the sheet has degenerated into a thin reflector element . This reflector element is highly sensitive to frequency changes. Flat sheet reflector or plane reflector Department of ECE

25. Department of ECE Corner Reflector

26. Department of ECE With two flat sheets intersecting at an angle α (α<180) as in fig (d), a sharper radiation pattern can be obtained. This arrangement is called an active corner reflector antenna . A corner reflector without an exciting antenna can be used as a passive reflector. Corner angle is always 90 for passive reflector. Reflector with this angle have the property that an incident wave is reflected back towards its source as in fig(e), the corner acting as a retro reflector. System Efficiency depend on the spacing between the vertex of the reflecto r and feed element S, That is ‘d’ Distance is adjusted by include angle Include angle decreases ,spacing between feed and reflector increased Corner Reflector

27. Department of ECE Parabolic or Curved Reflector Antennas A parabolic antenna is an antenna that uses a parabolic reflector ,or a curved surface with the cross-sectional shape of parabola , to direct the radio waves. A parabola may be defined as the locus of a point which moves in such a way that its distance from the fixed point (called focus) plus its distance from a straight line is constant. A parabola is a two dimensional plane curve. A parabola with focus F and vertex O is shown in figure.

28. Department of ECE The operating principle of a parabolic antenna : is that the radio waves at the focal point in front of a paraboloidal reflector of conductive material will be reflected into a collimated plane wave beam along the axis of the reflector . Conversely , an incoming plane wave parallel to the axis will be focused to a point at the focal point. Focal length : : The focal length of a parabola is the distance from it s focus to its vertex : The focal length of a parabola is the distance from its focus to i Working Principle

29. Department of ECE In fact, parabola converts a spherical wave front coming from the focus into a plane wave front at the mouth of the parabola as in fig . This results that the reflected ray is parallel to the parabolic axis, regardless of the particular value of Ө. i.e., All the waves originating from focus will be reflected parallel to the parabolic axis. This implies that all the wave reaching at the aperture plane are in phase. According to law of reflection, the angle of incidence and angle of reflection will be equal. Cont - Working Principle

30. Th e o p en m o u t h D of t h e pa r a b o l a i s k n own as the aperture. Paraboloidal reflector can be designed by keeping the mouth diameter fixed and varying the focal length f. The ratio of the focal length to aperture size i.e. f / D i s k n o wn as f o v er D r a t i o . I t s v a lue usually varies between 0.25 to 0.50 There are 3 possible cases. ( i ) f<D/4 (ii) f= D/4 (iii) f>D/4 Cases of Paraboloidal Department of ECE

31. In the first case, the focal length is small such that the focus lies well inside the mouth aperture. In this case it is difficult to get a source giving adequately uniform illumination over such a wide angle. In the second case, the focus lies in the plane of the open mouth. The focal length is equal to one fourth of open mouth diameter. (D/4) In the third case, when the focal length is large such that the focus lies beyond the open mouth, it becomes difficult to focus all the radiation from the source on the reflector. Department of ECE

32. Features of parabolic antenna Greater directivity and Gain . Parabolic or dish antennas are NOT frequency dependant. Receives and radiates signal in one direction only . Produce sharp and narrow beam width of any antenna types . R e duc t i o n i n s p i l l o v er a n d m i n or l o be radiation Simple in construction Quite inexpensive Ability to place feed in a convenient location. Department of ECE

33. Department of ECE High gain antennas for point to point communication. In applications such as microwave relay links that carry telephone and television signals between nearby cities. Wireless WAN/LAN links for data communications satellite and spacecraft communication antennas. Radio telescopes. Radar antennas. Satellite television dish antennas . Applications

34. 3 Cellular Comm. Technology Evolution 1G Voice 2003 M ulti- m edia 2 Mb/s 4G (LTE) 300 Mb/s 5G 2020 (?) 1980’s 1990’s 2000’s 2010’s 2020’s 2.5G GP R S 100 Kb/s 2G (GSM) 1990 9.6 Kb/s 3.5G HSPA 42 3G (UMTS M ) b/s L TE -A 1Gb/s 5G Department of ECE

35. Department of ECE 5G Technology Vision Data rates 10Gb/s. Low latency less than 1 ms can be achieved in 5G using mm wave. Hence traffic load is decreased on 5G base stations. Higher bandwidth can be used with the help of carrier aggregation feature. Dynamic beam forming is employed to overcome path-loss at higher frequencies. Improved 5G network architecture handoff will be smoother and hence it does not have any effect on data transfer when mobile user changes cell. 5G offers 10x throuhput,10x decrease in latency,10x connection density,3x spectrum efficiency,100x traffic capacity and 100x network efficiency.

36. Department of ECE Radio Approx. Frequency Band Main antenna: GSM/WCDMA/LTE Main, NR 617 MHz-6 GHz Aux Antenna 617 MHz-6 GHz 5G LTE MIMO3/MIMO4 1.8-6 GHz 5G mm-wave radio 24-40 GHz BT 2400-2485 MHz NFC 13.56 MHz GNSS 1575, 1610 MHz RFID 900 MHz Antenna Requirement in a 5G System

37. 5G antenna Technology Low bands below 1 GHz: longer range for e.g. mobile broadband and massive IoT e.g. 600 MHz, 700 MHz, 850/900 MHz Mid bands 1 GHz to 6 GHz: wider bandwidths for e.g. eMBB and mission- critical e.g. 3.4-3.8 GHz, 3.8-4.2 GHz, 4.4-4.9 GHz & LAA High bands above 24 GHz (mmWave): extreme bandwidths e.g. 24.25-27.5 GHz, 27.5-29.5, 37-40, 64-71 GHz Department of ECE

38. Department of ECE Rx Tx X1 X2 - Xn Y1 Y2 - Ym MIMO wireless System is a Combination of Multiple Transmit Antennas at transmitter in which Multiple inputs are provided to the wireless channels & Multiple Receive antennas at the receiver in which Multiple elements/sample are received as the output of the wireless communication channel . Radio Channel MIMO

39. 1.Driverless automobiles 2. Wireline convergence 3. Massive Machine Type Communications (mMTC) 4. Ultra Reliable and Low Latency Communications (URLLC) 5. Satellite access . 6. Vehicle-to-Everything (V2X) communications Department of ECE Applications of 5G

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