1 files changed, 19 insertions, 0 deletions
diff --git a/2219/CH3/EX3.18/Ex3_18.sce b/2219/CH3/EX3.18/Ex3_18.sce
new file mode 100755
index 000000000..9dbf5beb5
--- /dev/null
+++ b/2219/CH3/EX3.18/Ex3_18.sce
@@ -0,0 +1,19 @@
+// Chapter 3 example 18
+//------------------------------------------------------------------------------
+clc;
+clear;
+// let 'a' and 'b' be the broad and narrow dimensions of the rectangular guide and 'r' be internal radius of circular guide
+// Dominant mode in rectangular guide =TE10
+// cutoff wavelength = 2a
+// dominant mode in circular guide = TE11
+// cut-off wavelength = 2*pi*r/1.841  = 3.41r
+// for the two cut-off wavelengths to equal
+// 2a  = 3.41r
+// a = 1.705r
+// now area of cross section of rectangular guide = a*b
+//assuming a= 2b,which is very reasonable assumption ,we get 
+// area of cross section of rectangular waveguide = a*a/2 = ((1.705^2)*r*r)/2 = 1.453r^2
+// area of cross-section of circular guide = pi*r*r = 3.14r^2
+// ratio of two cross sectional areas = (3.14r^2)/(1.453r^2) = 2.16
+mprintf('Circular guide is 2.16 times larger in cross section as compared to rectangular guide');
+//------------------------------------------------------------------------------