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MITIGATION OF CHANNEL EFFECTS ON NEW RADIOS FOR 5G USING BEAM
FORMING AND BEAM COORDINATION
MELINA RAMPERSAND
TP0 31398
APU4F1910TE
TELECOMMUNICATION ENGINEERING
ASSOC. PROF. DR. SATHISH KUMAR SELVA PERUMAL
A project submitted in partial fulfillment of the requirement of For the degree of BEng (Hons) in Telecommunication Engineering ASIA PACIFIC UNIVERSITY OF TECHNOLOGY & INNOVATION FACULTY OF COMPUTING, ENGINEERING & TECHNOLOGY SCHOOL OF ENGINEERING JANUARY, 2020
TABLE OF CONTENTS:
1. INTRODUCTION
This lab report was conducted to conduct three different experiments in rectangular waveguides under the TE10 mode.
- OBJECTIVES 2.1. To determine the frequency & wavelength in a rectangular waveguide in TE 10 mode. 2.2. To determine the Standing Wave-Ratio and Reflection Coefficient. 2.3. To measure an unknown Impedance with Smith chart
- DESIGN ANALYTICAL EXPLAINATION AND CHARACTERISTICS OF INDIVIDUALBUILDING BLOCKS OF MICROWAVE LINK. The design and analytical explanation of the link is performed in this section of the report. The characteristics of the individual building blocks of the microwave is also discussed in this part. This report is a lab report consisting of 3 experiments that will all be conducted separately. The layout designing of all the 3 experiments will be described in the construction part of this report and the list of equipment needed are found to be as follows: 1. Klystron Power Supply, 2. 2k25 klystron mount, 3. Isolator, 4. Variable attenuator, 5. Frequency meter, 6. Slotted section, 7. Matched termination. 8. Tuneable probe, 9. SWR meter, 10. Microwave source, 11. S.S Tuner,
- Matched load. The figure below shows the complete et up of the above equipment mentioned that will be required to perform all the 3 experiments separately. The same setup will be required for all the 3 experiments however, every experiment of the design was modified according to the assignment criteria required stated in the microwave’s lab manual. The first block of the microwave link to be created is the Klystron Power Supply connection. A. DESIGN AND ANALYTICAL EXPLANATION EXPERIMENT 1 This experiment is carried out to find out the frequency and wavelength in a rectangular waveguide working under the TE 10 mode. The modes are shown in the waveguide as TEm,n or TMm,n where TE is the transverse electric and TM is the Transverse Magnetic, m is the number of half wavelength variation in broader direction and n is the number of half wave variation in shorter direction. For any electric field in a TE mode, it is transverse to the direction of propagation. Meanwhile, the magnetic field is normal to the propagation distance. The case is opposite for the electric field in TM mode. Figure 1 .0. Klystron power supply set up
The mode that can easily spread microwaves by having the least depletion is known as the most dominant mode. It can also be found that it has the lowest cut off frequency. EXPERIMENT 2 This experiment is set up to determine the standing wave ratio (SWR) and its reflective coefficient. The standing wave ratio is the least or maximum amount of voltage or the minimum or maximum current flowing into the transmission lines. The load effect is hence measured onto the transmission line and it can be concluded that the standing waves is the reflection of the two waves both having equal wavelength collision. The electromagnetic field off the transmission line can be categorised onto two different travelling waves which are incident and reflected waves. The incident wave is produced by the generator and the reflected wave flows towards the generator. The reflected wave is created through the impact of the incident wave. The sufficiency and the phase of the reflecting impedance will determine the extent and phase of the reflected wave. When the travelling waves are superposed together, it causes the standing wave to ascend the line. When the waves are both in phase, the quality of the transmission is very clear. SWR can be calculated by applying the following formula: 𝑆 = 𝐸𝑚𝑎𝑥 𝐸𝑚𝑖𝑛
𝐸𝐼+𝐸𝑅 𝐸𝐼−𝐸𝑅
Where: 𝐸𝑅 is the incident voltage 𝐸𝐼 is the reflected voltage ρ is the reflection coefficient 𝜌 =
Where: Z is the impedance at any specific point on the line 𝑍 0 is the characteristic impedance at any point on the line. EXPERIMENT 3 This section shows the experiment to measure any unknown impedance by using a Smith Chart. The impedance can be determined by using R + jX at any point of the transmission line. The SWR can be found and compared using the following equations. 𝑆 = 1 +𝑅 1 −𝑅
𝑍−𝑍 0 𝑍+𝑍 0
The unclear device connects to a free line and the SWR is set to zero. This will solve the minima position. The two distinct point for the minima is noted down the separation between them is found to be the guided wavelength, 𝜆𝑔and the minima is found to be an average value for the impedance. The detection of the minima and the maxima position is determined through unclear load and is set as ‘d’. The hover of the radius is equalled to S 0 and shown on the Smith Chart. A point on the circumference of the chart is found to be the load side having a separation of 𝑑 𝜆𝑔
. The point is then connected to the focal point of the chart. The normalized impedance will be shown by finding the coordinates of the points where the line cuts the circle.
signal connected to bencher hole set up a rotating field crosswise over bencher gap which made the electrons bundle up in various district. When they pass the catcher gap, they energize the catcher pit into reverberation. RF power is separated from catcher hole utilizing coupling gap.
- Isolator An isolator is a two-port device that transmits microwave or radio frequency in one direction. This device offers protection to the equipment on the input side from the effects of the load in addition to enhancing the stability of the device.
- Frequency Meter A frequency meter displays the frequency of a periodic electrical signal.
- Variable attenuator A variable attenuator is used to measure the SWR between the klystron power supply signal and the slotted section.
- Slotted Section The slotted section is used to measure standing waves, wavelength, and, with some calculation or plotting on Smith charts, reflection coefficient and impedance.
- Tuneable Probe A tuneable probe helps to obtain the maximum and minimum voltage of the waves depending on the SWR position.
- SWR Meter The SWR meter is used to measure SWR in a transmission line. This meter goes back to altering the voltmeter into a high gain low noise meter at fixed frequency. This device can also be used as a null detector in a bridge circuit or as a fixed frequency detector.
4. CONSTRUCTION OF THE EXPERIMENTAL SETUP
EXPERIMENT 1
To determine the frequency and wavelength in a rectangular waveguide working in TE 10 mode Apparatus needed:
- Klystron power supply
- Klystron tube
- Isolator
- Frequency meter
- Variable attenuator
- Slotted section
- Tuneable probe
- Wave guide stand
- SWR meter
- Matched termination Block diagram of experiment setup: Figure 2 .0. Block diagram for experiment 1
Procedures:
- The components and equipment were set up as shown in Figure 4.1.
- The variable attenuator was set to be at no attenuation position.
- The control knobs of the SWR meter were kept as the following:
- Range (dB): 50dB position
- Crystal: At 200 - ohm impedance
- Mode select: Normal position
- Gain (Course & Fine): Mid position
- SWR/dB: dB position
- The control knobs of the Klystron power supply were set as the following:
- Mode select switch: AM
- Beam voltage knob: Fully anticlockwise
- Reflector voltage: Fully clockwise
- AM-Amplitude knob: Fully clockwise
- AM-Frequency: Mid position
- The Klystron power supply, SWR meter and cooling fan were switched on.
- The beam voltage was set at 300V using the beam voltage knob while the current was set at around 15 to 20mA.
- The reflector voltage was adjusted to obtain some reading in the SWR meter.
- The reading was maximized using the AM amplitude and frequency control knob of the power supply.
- The plunger of the Klystron mount was tuned to obtain maximum reading.
- The reflector voltage knob was tuned for maximum reading on the SWR meter
- The probe was also tuned to obtain maximum reading in the SWR meter.
- The frequency meter was tuned to get a ‘dip’ on the SWR meter. The frequency was noted down directly from the frequency meter and the DRF was detuned.
- The tuneable probe was moved along with the slotted line to get a reading on the SWR meter. The tuneable probe was moved to a minimum reading position. The SWR meter
EXPERIMENT 2
To determine the Standing wave ratio and reflection coefficient. Apparatus needed:
- Klystron power supply
- Klystron tube
- SWR meter
- Isolator
- Frequency meter
- Variable attenuator
- Slotted line
- Tuneable probe
- Wave guide stand
- Matched termination
- BNC cable
- S-S tuner Block diagram of experiment setup: Figure 3 .0. Block diagram for experiment 2
Procedure:
- The components and equipment were set up based on the block diagram shown in figure 4.2.
- The variable attenuator was set to be at no attenuation position.
- The control knobs of the SWR meter were set as follows:
- Range (dB): 50dB position
- Crystal: At 200Ω
- Mode switch: Normal position
- Gain (Course & Fine): Mid position
- SWR/dB switch: dB position
- The control knobs of the Klystron power supply were set as follows:
- Mode select switch: AM
- Beam voltage knob: Fully anticlockwise
- Reflector voltage knob: Fully clockwise
- AM-Amplitude knob: Mid position
- AM-Frequency knob: Mid position
- The Klystron power supply, SWR meter and cooling fan were switched on.
- The beam voltage was set at 300V.
- The reflector voltage knob was adjusted to get some reading in the SWR meter.
- The output was tuned by tuning the reflector voltage, amplitude and frequency of AM modulation.
- The maximum reading was obtained by the plunger of Klystron mount. The probe was tuned for maximum reading.
- The range (dB) switch, variable attenuator position and gain control knob were changed to obtain a reading in the SWR meter.
- The reading was changed by moving the probe along with the slotted line. a. Measurement of low and medium SWR i. The S.S. tuner probe was set at no penetration position for low SWR.
𝜆𝑔 𝜋(𝑑 1 −𝑑 2 ) EXPERIMENT 3 To measure an unknown Impedance with Smith Chart Apparatus required:
- Klystron Tube 2K
- Klystron power supply
- Klystron mount
- SWR meter
- Isolator
- Frequency meter
- Variable attenuator
- Slotted line
- Tuneable probe
- Wave guide stand
- Matched termination
- S-S tuner Block diagram of the experimental setup Figure 4 .0. Block diagram for experiment 3
Procedure:
- The components and equipment were set up based on the block diagram shown in figure 4.3 above.
- The variable attenuator was set at no attenuation position.
- The S.S tuner and matched termination were connected after the slotted line.
- The control knobs of the SWR meter were set as follows:
- Range (dB): 50dB position
- Crystal: At 200Ω
- Mode switch: Normal position
- Gain (Course & Fine): Mid position
- SWR/dB switch: dB position
- The control knobs of the Klystron power supply were configured as the following:
- Mode select switch: AM
- Beam voltage knob: Fully anticlockwise
- Reflector voltage knob: Fully clockwise
- AM-Amplitude knob: Fully clockwise
- AM-Frequency knob: Mid position
- The Klystron power supply, SWR meter and cooling fan were switched on.
- The beam voltage was set at 300V.
- The reflector voltage was adjusted to obtain some reading on the SWR meter.
- The frequency meter knob was tuned to get a ‘dip’ on SWR scale. The frequency was then noted down directly from frequency meter. The meter was detuned from dip position.
- Guide wavelength was measured as follows: 𝜆𝑔 = 2(𝑑1 − 𝑑2)
- The depth of pin S.S. tuner was kept and locked to around 3-4mm.
- The probe was moved along with the slotted line to get a maximum reading.
