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L�B 1: ������� R������� Ch� ���� ������ (S�m������)
Mapping CO, PO, Domain, KI : CO2, CO3, PO3, P5
CO2: Analyze the parameters of antenna such as radiation pattern, impedance,
directivity, gain, polarization
CO3: Design and evaluate various antennas to meet application requirements
PO3: Identify, formulate and provide effective solution to engineering problem
L�� ���� O���m��:
1. Model a microstrip antenna in CST Microwave Studio Software
2. Observe and analyze the radiation characteristic of a microstrip antenna
parameters using CST Microwave Studio Software.
M�� �� �� ������� B��k� ���
Microstrip antennas, also called patch antennas, are very popular antennas in the
microwave frequency range because of their simplicity and compatibility with circuit
board technology. The rectangular patch antenna is one of the most commonly used
microstrip antennas. Edge-fed microstrip antennas are suited to direct integration
with microstrip circuits, since the antenna can be etched on the same substrate. When
sharing a substrate with microstrip circuits, the antenna performance is, however,
limited by the conflicting substrate requirements for antenna and circuit use. This
antenna is popular as an array-element, but for large arrays the feed-network
radiation may affect performance considerably.
Figure 1: The Structure of a Microstrip Antenna
Physical Description
Edge-fed patch antennas are usually manufactured by etching the antenna patch
element and feed network in a metallised dielectric substrate. Larger antennas are
sometimes constructed by bonding metal cut-outs to a bare substrate.
Feed Method
An edge-fed patch antenna is fed by a microstrip feed line connected to the edge of the
patch. The microstrip feed line usually incorporates a quarter-wave transformer for
impedance matching.
Operation Mechanism
The patch can be seen as a resonant cavity [Balanis] with radiating slots at each end of
the patch. The fringing fields act to extend the effective length of the patch, thus, the
length of the half-wave patch is usually less than a half wavelength in the dielectric
medium.
S�m������ �� CST M�� w�v� D����� S����
Good Habit
1. SAVE EARLY AND OFTEN
2. CST is notorious for crashing at the most inopportune times. Do yourself a
favor and save in your flash memory.
3. Make sure all components/structures are connected. Loose wires are a
frequent cause of problems.
4. Try your hand at debugging first before calling me ☺. You will learn a lot by
struggling through problems that seem hard at first.
5. Read all background behind the antenna and the lab instructions carefully
before starting the lab. Often, there will be a little detail that ends up being
very important.
CST Work Flow
1. Choose Project Template
2. Specify Units (� �q����� - GHz, T�m� – �� ��� D�m����� - �m)
3. Parameters + Geometry + Materials
4. Ports
5. Frequency-range + Boundaries / Symmetries
6. Monitor Definition
7. Quick Check Meshing
8. Run Simulation
Microstrip Antenna Modelling in CST Design Studio
1. Click “create project” and then select “Antennas”, then click “Next”
2. Select a Workflow
3. Select units
4. Create new template
5. Construct Substrate
6. New materials properties
7. Create ground
8. Create Patch
9. Create Feed
10. Create Matching Line
11. Creating Matching Line
12. Create Patch
13. Complete Structure
14. Port Setting
15. Port Setting
16. Boundary Condition
17. Background Properties and Frequencies
18. Time Domain Simulations
19. S11 Results
20. E-field at 2.3 GHz
21. Far-field at 2.3 GHz