Generalized Design from 170 GHz Anil Kumar Pandey Linear waveguide Slot array modeling in EMPro using parameterize variable for all components Slot array antenna Synthesis using python Script Calculation of antenna design parameters ID: 404829
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Slide1
Slotted Waveguide AntennaGeneralized Design from 1-70 GHz
Anil Kumar PandeySlide2
Linear waveguide Slot array modeling in EMPro using parameterize variable for all components
Slot array antenna Synthesis using python Script
Calculation of antenna design parameters
Changing these parameters in EMPro GUI hence Changing Antenna CAD file as per specified Frequency
Setting FEM Simulation parameters
Starting FEM Simulation
Input Parameters
Operating FrequencyNumber of Slots
Simulated Data
Array Antenna Design Flow in EMProSlide3
How a Waveguide Antenna WorksSlotted antenna arrays used with waveguides are a popular antenna in navigation, radar and other high-frequency systems.
A waveguide is a very low loss transmission line. It allows to propagate signals to a number of smaller antennas (slots). Each of these slots allows a little of the energy to radiate. Slot impedance and resonant behavior for a single slot are dependent on slot placement and size. Its exceptional directivity in the elevation plane gives it quite high power gain. The slotted waveguide has achieved most of its success when used in an omnidirectional role To make the unidirectional antenna radiate over the entire 360 degrees of azimuth, a second set of slots are cut in the back face of the waveguide. When looking straight at the face of the waveguide you will be able to see straight through both slots. Unfortunately, unless a lot of slots are used, the antenna becomes more like a bidirectional radiator, rather than an omnidirectional. Slide4
Length
Slot to Top
Slot length
Slot Offset
Wg_a
Slot Width
Linear Array Sketch
Parameters of waveguide slot array design
Distance from portSlide5
Various Linear Array Combinations
N : No of Slots Variation
(F : Fixed)
F : Operating Frequency
(N : Fixed)
No of slots and Frequency are two variable input parameter . Varying these two parameters many combination of array antenna can be designed
60 GHz
30 GHz
13.2 GHz
2.44 GHz
64 slots
32 slots
16 slotsSlide6
Slot Array Design Formulas
lam_zero
=300/
FGHz
# Free space wavelength
WG_a
= (
lam_zero
/2)+(
lam_zero
*0.2) # Auto calculation of broad (a) dimension of waveguide
WG_b
=
WG_a
/2 # Height (b)of waveguide
PI=3.14
lam_cutoff
=2*
WG_a
lam_guide
=1/
sqrt
(((1.0/
lam_zero
)**2)-((1.0/
lam_cutoff
)**2))
# Slot offset
G_2_slot=1.0/
Nslots
New_G1=2.09*(
lam_guide
/
lam_zero
)*(
WG_a
/
WG_b
)*(cmath.cos(0.464*PI*
lam_zero
/
lam_guide
)-cmath.cos(0.464*PI))**2
New_Y
=G_2_slot/New_G1
Soff
=(
WG_a
/PI)*
sqrt
(abs(
cmath.asin
(
New_Y
)))
# Slot
Lenght
Slot_wl
=0.210324*G_2_slot**4-0.338065*G_2_slot**3+0.12712*G_2_slot**2+0.034433*G_2_slot+0.48253
Sl
=
lam_zero
*
Slot_wl
#Slot width
Sw
=
WG_a
*0.0625/0.9
#Slot Spacing
Ss=
lam_guide
/2
# Distance from short ( end space)
S_top
=
lam_guide
/4
#Estimated Performance
Gain=abs(10 * cmath.log10((
Nslots
/2) *
lam_guide
/
lam_zero
)) #dB
Beamwidth=50.7 *
lam_zero
/ ((
Nslots
/2)*(
lam_guide
/2)) #degreeSlide7
Working Model
This is generalized example of slot array antenna from 1 GHz to 70 GHz. This example uses powerful feature of EMPro python scripting for slot array parameters calculation and parameterize feature of EMPro to create generalized example.
Open the project in EMPro
Double click synthesis script present in project
Enter desired operating frequency and number of slots
Run script, it will automatically calculate all design parameters, set parameters in GUI and modified CAD file as per specified frequency and launch FEM simulation
Other Tips
If you don’t want to launch FEM simulation , comment below two lines in script
#
setupSimulation
(FGHz-1, FGHz+1, 25 )
#return
empro.activeProject.addSimulationDataToProject
(
autoQueue
)Slide8
Gain-9.69 dBi
Simulation time- 22Min 47 sec
Unknown - 0.2 Million
Memory – 400 MB (Iterative)
Array Antenna Performance at 2.41 GHz
WAN: antenna for 2.44GHz, or channel 7
Slotted Waveguide
802.11b WLAN antennasSlide9
Gain-10.48 dBi
Simulation time- 32Min 41 sec
Unknown - 0.3Million
Memory – 400 MB (Iterative)
Array Antenna Performance at 6 GHzSlide10
Gain- 11.43dBi
Array Antenna Performance at 27 and 60 GHz