Slotted Waveguide Antenna PowerPoint Presentation, PPT - DocSlides

Slotted Waveguide AntennaGeneralized Design from 1-70 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

Changing these parameters in EMPro GUI hence Changing Antenna CAD file as per specified FrequencySetting FEM Simulation parametersStarting FEM Simulation

Input Parameters

Operating FrequencyNumber of Slots

Simulated Data

Array Antenna Design Flow in EMPro

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.

Length

Slot to Top

Slot length

Slot Offset

Wg_a

Slot Width

Linear Array Sketch

Parameters of waveguide slot array design

Distance from port

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 slots

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)) #degree

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

)

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 antennas

Gain-10.48 dBi

Simulation time- 32Min 41 secUnknown - 0.3MillionMemory – 400 MB (Iterative)

Array Antenna Performance at 6 GHz

Gain- 11.43dBi

Array Antenna Performance at 27 and 60 GHz