RECONFIGURABLE MAGNETOHYDRODYANAMIC ANTENNA

Transcription

1 RECONFIGURABLE MAGNETOHYDRODYANAMIC ANTENNA

2 LITERATURE SURVEY RECONFIGURABLE ANTENNA It was first introduced in 1998 by E.R Brown The most common techniques utilized in designing reconfigurable antenna is switching mechanism. Switches like MEMS and PIN diodes were used to achieve reconfigurability. This switching mechanism basically redistribute the antenna current Schottky diodes have higher insertion loss as compared to PIN diodes Reconfigurable antenna are also designed using capacitor and varactors different biasing segment scheme [8] can also be used to achieve reconfigurability. The reconfigurability is also achieved by making use of Switch reconfigured feeding scheme

3 PATCH ANTENNA A microstrip patch antenna consists of conducting patch of any planar or non planar geometry on one side of dielectric substrate with a ground plane on other side They were first described by Howell in 1972 The main disadvantages of patch antenna are low efficiency. Narrow bandwidth is one of the important drawback of patch antenna Comprehensive research work has been done to develop some bandwidth enhancement techniques. Use of thick substrate improves bandwidth to a very limited extend

4 It was also analyzed that by loading of some specify slot in micro strip antenna,compact or reduced size microstrip antenna can be obtained. The techniques like square-ring patch fed by a micro strip line The use of cross end bent slots embedded in the radiating patch The use of slot in ground plane

5 DIELECTRIC RESONATOR ANTENNA Dielectric resonator antenna was first introduced by S.A. Long in 1980 Many research papers have been published in reputed journals by researcher such as Kishk [23], Lee [24], Leung [25], Luk [26], Mongia [27], Shum [28], Junker [22], Antar [29], and Petosa [30],a lot of research work was carried out on realizing various analytical and numerical technique for the design of antenna in 1990 broad band and ultra-wideband DRA structures are still suffering from some designing disadvantages making them less competitive such as complex geometries The major limitation of DRA is its low gain.

6 The research is going on to increase the gain of DRA. Researchers have increased the gain to some extent by employing an offset dual disk dielectric resonator (DR) [34].,stacking parasitic DR with an air gap between the driven and parasitic DRs [35] and using composite layered DR of high permittivity[36].all this research work resulted in gain improvement of 2.7 db as compared to single DRA element.

7 GAP ANALYSIS Most of the work has been done on patch and microstrip antenna Low gain and less bandwidth have limited their usage There are very less work of hybrid design of patch with DRA for getting enhanced bandwidth and gain Antenna reconfigurability is basically obtained through the use of electronic switches like RF MEMS, P-I-N diode and photo conductive switches Use of switch to obtain reconfigurability, causes losses.hence research is required to investigate some better technique to achieve reconfigurability.

8 AIM OF RESEARCH WORK Investigation on Reconfigurable, optimization of gain and bandwidth of antenna. Reconfiguration in antenna by three different ways: Frequency Reconfigurable antenna Gain Reconfigurable antenna Polarization Reconfigurable antenna Gain enhancement using superstrate structure Bandwidth enhancement using mode merging

9 SIGNIFICANCE OF HIGH GAIN AND LARGE BANDWIDTH ANTENNA Current speed of Mb/s is insufficient for future applications Wireless high quality video conferencing, need 10Gbps for 5G Long distance communication Multiple wireless connections,hence there is a demand for higher data rates. Microwave Communication, Line of sight communication, Satellite communication and software defined radios require pencil beam to establish stable and efficient communication

10 SIGNIFICANCE OF RECONFIGURABLE ANTENNA Scope of Reconfigurable Antenna Covers several frequency bands concurrently with a single antenna. Significant reduction in overall size of multiband wireless communication system. Can reduce system complexity and cost. With increased spectrum usage, the use of reconfigurable antenna is being considered as one of the method for improving spectrum range.. Today s wireless communication have initiated the need to club various services on a single device. Hence there is a need of antenna that can cover various frequency bands and can provide variable gain

11 SIGNIFICANCE OF POLARIZATION RECONFIGURABLE ANTENNA Polarisation diversity plays a vital role in wireless local area network,as by making use of them fading caused by multipath effect can be minimized. In the proposed designed antenna,switching between RHCP and LHCP can be achieved at the same frequency.hence,it offers frequency reuse.hence provides conservation of spectrum and doubling the system capability Robust Secrecy

12 MOTIVATION.The success of any wireless link depends on wireless product performance which is completely dependent on a high performance antenna design and implementation. The stringent requirements need advanced developments in this field of antenna having low profile, high gain and ultra large bandwidth with reconfigurability

13 DIFFERENT TYPES OF ANTENNA DESIGN USED IN RESEARCH WORK Patch Antenna Dielectric Resonator Antenna(DRA) Cylindrical Dielectric Resonator Antenna Rectangular Dielectric Resonator Antenna Hybrid combination of Patch and Dielectric Resonator Antenna(DRA) applying Magneto hydrodynamic (MHD) Technique

14 INVESTIGATIONS DONE TO ACHIEVE THE AIM

15 INVESTIGATIONS FOR ANTENNA GAIN ENHANCEMENT Design of antenna having hybrid combination of patch and DRA and applying Magnetohydrodyanamic technique to hybrid combination A new technique to generate higher order modes in rectangular DRA to enhance gain and bandwidth of antenna has been proposed, higher order modes imparts higher gain and neighboring mode merging results into enhanced bandwidth The design consists of hybrid structure of patch and DRA, operated under controlled electric field and magnetic field and the he design is loaded with superstrate

16 INVESTIGATIONS TO ACHIEVE ANTENNA GAIN AND FREQUENCY RECONFIGURABILITY An antenna having hybrid combination of patch and DRA, applying Magnetohydrodyanamic has been designed.the designed antenna offers gain as well as frequency reconfigurability. A Reconfigurable aperture coupled Rectangular Dielectric Resonator antenna (RDRA) has been designed.the effect of varying the angular orientation of slot on the radiation characteristics and gain of the RDRA is investigated. It has been investigated that change in angular orientation of slot in aperture coupling feeding scheme can significantly affect the radiation properties and gain of RDRA.

17 INVESTIGATIONS TO ACHIEVE ANTENNA POLARISATION RECONFIGURABILITY A novel design of polarization reconfigurable,left hand and right hand switchable cylindrical DRA by using two crossed slots of unequal length to couple energy from an aperture coupled micro strip line has been proposed

18 CYLINDRICAL INHOMOGENEOUS DIELECTRIC MAGNETO-HYDRO- DYNAMIC ANTENNA

19 ABSTRACT A hybrid design of Patch and DRA, applying MHD technology has been investigated. This Embedded technique results in high gain and Reconfigurability. Stacked cylindrical DRA,s placed on concentric annular rings of dissimilar diameters. Hybrid structure filled with mixture of Silicon oil and Barium Strontium Titanate has been operating under controlled electric fields and H-magnetic fields to produce Lorentz Force on the conducting fluid. When applied electric bias to fluid resonator was varied from 5V to 30V i.e. Antenna Gain also varied from 1.5 db to db.

20 INTRODUCTION Reconfigurable antenna represents a recent innovation in Antenna design that changes from conventional fixed form to modifiable structure that can be adapted to fit the current trends in wireless communication

21 ANTENNA STRUCTURE

22 DIMENSIONS OF MHD ANTENNA

23 SIMULATED AND EXPERIMENTAL RESULTS The designs have been simulated using Ansoft high frequency simulator (HFSS).

24 MEASURED REFLECTION COEFFICIENT CHARACTERISTICS AS THE FUNCTION OF FREQUENCY OF ANTENNA

25 RADIATION PATTERN AND GAIN OF ANTENNA,WITH COMPLETE STRUCTURE OF CONCENTRIC ANNULAR RINGS EMBEDDED WITH DRA. GAIN MEASURED WAS 1.5 DB.

26 S11 IN DB VS FREQ (GHZ) WHEN VARIABLE D.C. BIAS VOLTAGE APPLIED

27 RADIATION PATTERN SHOWING GAIN INCREASED TO 7.79DB AT 5V DC

28 RADIATION PATTERN SHOWING GAIN INCREASED TO 9.67 DB AT 20V DC

29 RADIATION PATTERN SHOWING GAIN INCREASED TO 11.09DB AT30 V DC

30 S11 UNDER MAGNETIC BIAS 2500 TESLA

31 RADIATION PATTERN WITH ELECTRIC AND MAGNETIC BIASING IS APPLIED AT SAME TIME. GAIN DECREASED TO 6.45 DB BUT BANDWIDTH INCREASED.

32 EXPERIMENTAL MEASUREMENT SHOWING PROTOTYPE ANTENNA

33 RESULTTS DC bias Voltage Resonant Frequency(GHz) Return Loss(db) Gain(db) 0V V V V

34 CONCLUSION Design of this antenna offers wide scope of achieving high gain, Different values. of D.C bias voltage fetched different gain. Smart antenna. Best utilized for software defined radio and military applications.

35 INVESTIGATIONS ON HIGH GAIN AND WIDEBAND RECTANGULAR DRA

36 ADVANTAGES OF RECTANGULAR DRA Design flexibility having two aspect rato b/a.d/a Varying aspect ratio,higher modes can be generated. High radiation efficiency Light weight Low profile

37 MODES OF ANTENNA Modes of antenna are defined as E,H field pattern inside the device,whose EM waves propogation is governed by Maxwell equation Resonant modes are Transverse Electric(TE),only Hz component as propagating field when, Ez = 0. Transverse Magnetic(TM),only Ez component, when Hz = 0 Hybrid Electromagnetic(HEM), both Ez and Hz components Geneartion of Higher order modes corresponds to higher gain

38 VARIOUS MODES SKETCHES

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40 Generation of higher modes results higher gain Investigation invoved Increasing Height of DRA,results in higher mode Generation Changing the excitation frequency,also results in generation of higher order mode. Placing additional DRA on top of existing DRA with an spacer s and excited by another aperture coupled micro strip line. Investigating DRA of a particular height with or witout placing additional DRA on top Spacing s is acting as controller of the bandwidth of Dielectric Resonator Antenna

41 OBSERVATION Higher order modes can be generated in two ways Increasing RDRA height Increasing input excitation frequency. Placing additional DRA on top of existing DRA with an spacer s and excited by another aperture coupled micro strip line.

42 DESIGN STRUCTURE OF RDRA

43 - GAIN OF SIMULATED RDRA AT VARIOUS HEIGHT

44 ANTENNA STRUCTURE WITH TOP LOADING

45 OBSERVATION

46 RETURN LOSS FOR DR HEIGHTH=5MM.

47 RETURN LOSS FOR DR HEIGHTH=15MM.

48 RETURN LOSS FOR DR H=30MM.

49 OBSERVATIONS It was seen in RDRA of particular height More number of higher-order mode can be excited by applying another excitation on the top of RDRA. The reduced spacing s between top and bottom RDRAs, merged even modes, thus increased bandwidth of the antenna. The RDRA under top loading converted few odd modes to nearest even mode. Thus, both even and odd modes were made available due to top loading.merging of adjacent bands or neighboring modes of RDRA can be used for enhancement of the bandwidth

50 HIGHER ORDER ODD AND EVEN MODES

51 HIGHER ORDER EVEN MODES

52 CONTROL OF BANDWIDTH THROUGH SPACING S

53 APPLICATIONS.High gain, miniaturization, high band width, directive antenna

54 RDRA ANTENNA READY FOR TEST PROCEDURE SETUP

55 RDRA ANTENNA IN ANEORICH CHAMBER

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57 APPLICATIONS By developing control on modes, We can control beam width of antenna and can restrict the reception of signal to a particular area and hence it can be used for military applications. Presently, we face the problem of TV signal reception during rainy season, due to the absorption of signal by rain drops due to signal being single polarized either TE or TM. The other application could be miniaturization of antenna. To automate the mode generation, microcontroller-based lookup table can generate possible combinations of bandwidth

58 SUPERSTRATE EMBEDDED HYBRID MHD ANTENNA

59 NEED OF HIGH GAIN ANTENNA Current speed of Mb/s is insufficient for future applications Wireless high quality video conferencing Multiple wireless connections,hence there is a demand for higher data rates.

60 DESIGN OF SUPERSTRATE ANTENNA

61 DESIGN DIMENSIONS OF ANTENNA

62 db(st(pin_t1,pin_t1)) SIMULATED S XY Plot 5 HFSSDesign1 Curve Info db(st(pin_t1,pin_t1)) Setup2 : Sw eep1 ANSOFT Freq [GHz]

63 EXPERIMENTAL RESULTS OF S11

64 SIMULATED RESULTS OF GAIN 6DB WITHOUT SUPERSTRATE

65 RADIATION PATTERN WITH PEAK GAIN 9.8 DB WITH SUPERSTRATE Radiation Pattern 2 HFSSDesign1 ANSOFT Curve Info db(gaintotal) Setup2 : LastAdaptive Freq='4GHz' Phi='0deg' db(gaintotal) Setup2 : LastAdaptive Freq='4GHz' Phi='10deg' db(gaintotal) Setup2 : LastAdaptive Freq='4GHz' Phi='20deg' db(gaintotal) Setup2 : LastAdaptive Freq='4GHz' Phi='30deg' db(gaintotal) Setup2 : LastAdaptive Freq='4GHz' Phi='40deg' db(gaintotal) Setup2 : LastAdaptive Freq='4GHz' Phi='50deg' db(gaintotal)

66 Z11 IMPEDANCE

67 H FIELD PATTERN INSIDE DRA

68 RESULT SUMMARY

69 ADVANTAGES Utilisation of Unlicensed frequency band High gain Protection against Environment

70 APPLICATION Underground Communication Superstrate antennas are used where protection against environment is required

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72 POLARIZATION LINEAR POLARZATION Linear polarization

73 CIRCULAR POLARISED Left hand Circular Polarization Right hand Circular Polarization

74 ELLIPTICAL POLARISATION

75 DIMENSIONS OF THE DESIGN Sr No. Element Dimension(mm) 1 Substrate 120X120X (Er RogersRT Duroid 5880 =2.2) 2 Ground Plane 120*120 3 Microstrip line 50 ohms 2.4*100 4 Slot *0.3 5 Slot 2 8.9*0.3 6 Stub Stub Cylindrical DRA Radius 15.2(Er Roger TMM 10i = 9.8) 9 Cylindrical DRA Height Radiation Box 120*120*36 11 Lumped Port 12*3.1496

76 DESIGN OF CROSS COUPLED DRA FOR CIRCULAR POLARIZATION

77 CONTINUED...

78 RESULTS, S11 RETURN LOSS (LHCP)

79 mag(z(1,1)) INPUT IMPEDANCE (LHCP) Z11 HFSSDesign1 Curve Info mag(z(1,1)) Setup1 : Sw eep Name X Y m m m The resistance is close to 50 ohms at three points of slot and DRA resonant freq m1 m m Freq [GHz]

80 VSWR (LHCP)

81 AXIAL RATIO (LHCP)

82 ANTENNA GAIN (db) LHCP GAIN AND CROSS POLARIZATION GAIN Gain Antenna Gain (LHCP) at Phi 0,90. HFSSDesign1 Curve Info db(gainlhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(gainlhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' db(gainrhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(gainrhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' Antenna Gain (RHCP) at Phi 0, RHCP (cross polarization) gain down by -15db m1 Name X Y m Theta [deg]

83 RADIATION PATTERN Radiation Pattern 1 HFSSDesign1-60 LHCP Radiation Pattern Curve Info db(relhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(relhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' db(rerhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(rerhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' Cross Polarisation Radiation Pattern

84 Y POLARIZATION RATIO The polarization ratio is the ratio of the orthogonal polarizations Polarization Ratio Curve Info HFSSDesign1 db(polarizationratiocircularlhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(polarizationratiocircularlhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' db(polarizationratiocircularrhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(polarizationratiocircularrhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' 0.00 At theta = -10 we are getting max diff between the two polazations m1 Name X Y m Theta [deg]

85

86 RHCP OPERATION For Rhcp operation the slots are rotated by 90deg

87 S11 RETURN LOSS (RHCP)

88 mag(z(1,1)) INPUT IMPEDANCE (RHCP) Z11 HFSSDesign1 Curve Info mag(z(1,1)) Setup1 : Sw eep The resistance is close to 50 ohms at three points of slot and DRA resonant freq m3 m m Name X Y m m m Freq [GHz]

89 VSWR (RHCP)

90 AXIAL RATIO (RHCP)

91 Antenna Gain (db) RHCP GAIN AND CROSS POLARIZATION GAIN Gain Antenna Gain (RHCP) at Phi 0,90. HFSSDesign1 Curve Info db(gainrhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(gainrhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' db(gainlhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(gainlhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' Antenna Gain (LHCP) at Phi 0, LHCP (cross polarization) gain down by -15db Theta [deg]

92 RADIATION PATTERN Radiation Pattern 1 HFSSDesign RHCP Radiation Pattern 60 Curve Info db(relhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(relhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' db(rerhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(rerhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' 4.00 Cross polarization Radiation Pattern

93 Y1 POLARIZATION RATIO The polarization ratio is the ratio of the orthogonal polarizations Polarization Ratio Curve Info HFSSDesign1 db(polarizationratiocircularlhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(polarizationratiocircularlhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' db(polarizationratiocircularrhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='0deg' db(polarizationratiocircularrhcp) Setup1 : LastAdaptive Freq='5.75GHz' Phi='90deg' Theta [deg]

94

95 FUTURE WORK Protype of antenna is to be designed To develop the mechanism of automation of switching

96 ADVANTAGES Frequency reuse Conservation of Spectrum

97 THANK YOU!