STUDY THE MICROWAVE DIELECTRIC PROPERTIES OF B2O3 DOPED Nd(Mg0.5)O3 CERAMIC AND ITS APPLICATION ON PLANAR INVERTED L ANTENNA GVHD ：Dr. YIH-CHIEN CHEN SVTH ：HỒ NGUYỄN BẢO PHƯƠNG MSSV : 060632D LỚP : 06DD2D KHÓA : 10 SVTH : HỒ NGUYỄN BẢO PHƯƠNG MSSV :060632D LỚP :06DD2D CONTENTS 1 CHAPTER 1: PROPERTIES OF ELECTROMAGNETIC .2 PLANE WAVE PROPERTIES. 9 2 CHAPTER 2: PROPAGATION MECHANISMS .2 ROUGH SURFACE SCATTERING. 12 3 CHAPTER 3:ANTENNA FUNDAMENTALS .1 NECESSARY CONDITIONS FOR RADIATION .2 NEAR-FIELD AND FAR-FIELD REGIONS .3 FAR-FIELD RADIATION FROM WIRES .5 RADIATION RESISTANCE AND EFFICIENCY.
22 4 CHAPTER 4: PRACTICAL ANTENNA .3 REflECTOR ANTENNAS. 27 5 CHAPTER 5: THE MICROSTRIP ANTENNA DESIGN.2 BASIC MICROSTRIP LINE .3 MICROSTRIP FIELD RADIATION. 33 2 LUẬN ÁN TỐT NGHIỆP SVTH : HỒ NGUYỄN BẢO PHƯƠNG MSSV :060632D LỚP :06DD2D 5.5 BASIC MICROSTRIP ANTENNA.6 BASIC CONFIGURATION OF MICROSTRIP ANTENNA .7 RADIATED FIELDS OF MICROSTRIP ANTENNA. DISADVANTAGES OF MICROSTRIP ANTENNAS .10 TYPES OF MICROSTRIP ANTENNAS.11 MICROSTRIP TRAVELING -WAVE ANTENNAS.12 MICROSTRIP SLOT ANTENNAS .15 MICROSTRIP LINE FED ANTENNAS.
43 6 CHAPTER 6 : PRODUCTION PROCESS .1 PREPARE COMPOUND NMZS:.2 Calculated the balanced of chemical formula : .3 Powder weight reduced three fold: .4 Make up NMZS:. 48 7 CHAPTER 7: STUDY THE MICROWAVE DIELECTRIC PROPERTIES OF B2O3 DOPED ND(MG0.5)O3 CERAMIC AND ITS APPLICATION ON PLANAR INVERTED L ANTENNA .3 ANTENNA DESIGN STRUCTURE: .6 ANALYSIS RESULTS AND DISCUSSION:. 63 3 LUẬN ÁN TỐT NGHIỆP SVTH : HỒ NGUYỄN BẢO PHƯƠNG MSSV :060632D LỚP :06DD2D Figure 7-1: Geometry of the PILA antenna .52 7-6 : The X-ray diffraction patterns of Nd(Mg0.5)O3 specimens with different amounts of B2O3 additives sintered at 1450◦C for 4h.53 7-7: The X-ray diffraction patterns of Nd(Mg0.5)O3 specimens with different amounts of B2O3 additives sintered at 1400◦C for 4h.53 7-8 :The X-ray diffraction patterns of Nd(Mg0.5)O3 specimens with different amounts of B2O3 additives sintered at 1350◦C for 4h.1 wt% B2O3 doped NMZS .55 7-12:The apparent densities of Nd(Mg0.5)O3 ceramics with different amounts of B2O3 additives sintered in the range of 1300 to 1500◦C for 4h.56 7-13:shows the dielectric constants of Nd(Mg0.5)O3 ceramics with different amounts of B2O3 additive sintered at different temperatures for 4h.56 7-14 :The Q×f of of Nd(Mg0.5)O3 ceramics with different amounts of B2O3additives sintered in the range of 1300 to 1450◦C for 4h.57 7-15 :The τf of Nd(Mg0.5)O3 ceramics with different amounts of B2O3additive sintered at different temperatures for 4 h.59 4 LUẬN ÁN TỐT NGHIỆP SVTH : HỒ NGUYỄN BẢO PHƯƠNG MSSV :060632D LỚP :06DD2D 1 Chapter 1: PROPERTIES OF ELECTROMAGNETIC 1.1 Maxwell’ Equation : The existence of propagating electromagnetic waves can be predicted as a direct consequence of Maxwell‟s equations [Maxwell, 1865]. These equations specify the relationships between the variations of the vector electric field E and the vector magnetic field H in time and space within a medium.
The E field strength is measured in volts per metre and is generated by either a time-varying magnetic field or a free charge. The H field is measured in amperes per metre and is generated by either a time-varying electric field or a current. Maxwell‟s four equations can be summarised in words as An electric field is produced by a time-varying magnetic field. A magnetic field is produced by a time-varying electric field or by a current Electric field lines may either start and end on charges; or are continuous Magnetic field lines are continuous.
The first two equations, Maxwell‟s curl equations, constain constants of proportionality which dictate the strengths of the fields. These are the permeability of the medium µ in the henrys per metre and permittivity of the medium Ɛ in the farads per metre. They are normally expressed relative to the value of free space: Ɛ=ƐrƐ0 µ0=4π x 10-7 Hm-1 µ=µrµ0 Ɛ0=8.854 x 10-12 Fm-1 Ɛr, µr =1 in the free space. Free space strictly indicates a vacuum, but the same value can be used as good approximations in dry air at typical temperatures and pressures.2 Plane Wave Properties : Many solutions to Maxwell‟s equations exist and all of these solutions represent fields which could actually be produced in practice.
However, they can all be represented as a sum of plane waves, which represent the simplest possible time varying solution. Figure shows a plane wave, propagating parallel to the z-axis at time t = 0. 5 LUẬN ÁN TỐT NGHIỆP SVTH : HỒ NGUYỄN BẢO PHƯƠNG MSSV :060632D LỚP :06DD2D The electric and magnetic fields are perpendicular to each other and to the direction of propagation of the wave; the direction of propagation is along the z axis; the vector in this direction is the propagation vector or Poynting vector. The two fields are in phase at any point in time or in space.
Their magnitude is constant in the xy plane, and a surface of constant phase (a wavefront) forms a plane parallel to the xy plane, hence the term plane wave. The oscillating electric field produces a magnetic field, which itself oscillates to recreate an electric field and so on, in accordance with Maxwell‟s curl equations. This interplay between the two fields stores energy and hence carries power along the Poynting vector. Variation, or modulation, of the properties of the wave (amplitude, frequency or phase) then allows information to be carried in the wave between its source and destination, which is the central aim of a wireless commu- nication system.3 Diffraction: Principle The geometrical optics field described in Section 3.4 is a very useful description, accurate for many problems where the path from transmitter to receiver is not blocked.
However, such a description leads to entirely incorrect predictions when considering fields in the shadow region behind an obstruction, since it predicts that no field whatsoever exists in the shadow region as shown in Figure 3. This suggests that there is an infinitely sharp transition from the shadow region to the illuminated region outside. In practice, however, shadows are never completely sharp, and some energy does propagate into the shadow region. This effect is diffraction and can most easily be understood by using Huygen‟s principle.
Each element of a wave front at a point in time may be regarded as the centre of a secondary disturbance, which gives rise to spherical wavelets. The position of the wave front at any later time is the envelope of all such wavelets. 6 LUẬN ÁN TỐT NGHIỆP SVTH : HỒ NGUYỄN BẢO PHƯƠNG MSSV :060632D LỚP :06DD2D 1.4 Field Relationships : The electric field can be written as E=E0cos(ωt-kz)x^ where E0 is the field amplitude [V m -1], ω=2πf is the angular frequency in radians for a frequency f [Hz], t is the elapsed time [s], k is the wave number [m 1], z is distance along the z-axis (m) and ^x is a unit vector in the positive x direction. The wave number represents the rate of change of the phase of the field with distance; that is, the phase of the wave changes by kr radians over a distance of r metres.
The distance over which the phase of the wave changes by 2 π radians is the wavelength λ. Thus : k=2π/λ Similarly, the magnetic field vector H can be written as H=H0Cos(ωt-kz)y^ where H0 is the magnetic field amplitude and ^y is a unit vector in the positive y direction. The medium in which the wave travels is lossless, so the wave amplitude stays constant with distance. Notice that the wave varies sinusoidally in both time and distance.5 Poynting Vector : The Poynting vector S, measured in watts per square metre, describes the magnitude and direction of the power flow carried by the wave per square metre of area parallel to the xy plane, i.
the power density of the wave. Its instantaneous value is given by S = E x H* Usually, only the time average of the power flow over one period is of concern Sav= E0H0z^ The direction vector in Eq emphasises that E, H and Sav form a right-hand set, i. Sav is in the direction of movement of a right-handed corkscrew, turned from the E direction to the H direction.6 Phase Velocity : The velocity of a point of constant phase on the wave, the phase velocity v at which wave fronts advance in the S direction, is given by V= Hence the wavelength λ is given by λ= 7 LUẬN ÁN TỐT NGHIỆP SVTH : HỒ NGUYỄN BẢO PHƯƠNG MSSV :060632D LỚP :06DD2D 1.7 Polarisation States : The alignment of the electric field vector of a plane wave relative to the direction of propagation defines the polarisation of the wave.1 the electric field is parallel to the x axis, so this wave is x polarised. This wave could be generated by a straight wire antenna parallel to the x axis.
An entirely distinct y- polarised plane wave could be generated with the same direction of propagation and recovered independently of the other wave using pairs of transmit and receive antennas with perpendicular polarisation. This principle is sometimes used in satellite communications to provide two independent communication channels on the same earth satellite link. If the wave is generated by a vertical wire antenna (H field horizontal), then the wave is said to be vertically polarised; a wire antenna parallel to the ground (E field horizontal) primarily generates waves that are horizontally polarised. The waves described so far have been linearly polarised, since the electric field vector has a single direction along the whole of the propagation axis.
If two plane waves of equal amplitude and orthogonal polarisation are combined with a 90 phase difference, the resulting wave will be circularly polarised (CP), in that the motion of the electric field vector will describe a circle centred on the propagation vector. The field vector will rotate by 360 for every wavelength travelled. Circularly polarised waves are most commonly used in satellite communications, since they can be generated and received using antennas which are oriented in any direction around their axis without loss of power. They may be generated as either right-hand circularly polarised (RHCP) or left-hand circularly polarised (LHCP); RHCP describes a wave with the electric field vector rotating clockwise when looking in the direction of propagation.
In the most general case, the component waves could be of unequal amplitudes or at a phase angle other than 90. The result is an elliptically polarised wave, where the electric field vector still rotates at the same rate but varies in amplitude with time, thereby describing an ellipse. In this case, the wave is characterised by the ratio between the maximum and minimum values of the instantaneous electric field, known as the axial ratio, AR, AR = Wave Impedance Maxwell‟s equations, provided the ratio of the field amplitudes is a constant for a given medium, 8 LUẬN ÁN TỐT NGHIỆP SVTH : HỒ NGUYỄN BẢO PHƯƠNG MSSV :060632D LỚP :06DD2D where Z is called the wave impedance and has units of ohms. In free space, µ0, µr=1 and 1.8 Lossy Media : So far only lossless media have been considered.
When the medium has significant con- ductivity, the amplitude of the wave diminishes with distance travelled through the medium as energy is removed from the wave and converted to heat And The constant a is known as the attenuation constant, with units of per metre [m - 1], which depends on the permeability and permittivity of the medium, the frequency of the wave and the conductivity of the medium, measured in siemens per metre or per- ohm-metre [ Ω m] -1. Together Ɛ ,µ and are known as the constitutive parameters of the medium. In consequence, the field strength (both electric and magnetic) diminishes exponentially as the wave travels through the medium as shown in Figure 2. The distance through which the wave travels before its field strength reduces to e- 1 = 0.