Structure of the ionosphere, critical frequency, and skip distance. 5. Transmission Lines and Waveguides
If you cannot afford the physical book, use the Google Books link to copy the exact ISBN, then search that ISBN on your university’s library portal. Most engineering libraries have three or four copies in the "Reserve" section. antenna and wave propagation by kd prasad google books link
Here is the text regarding the book and its availability on Google Books, along with the direct link. Structure of the ionosphere, critical frequency, and skip
I will cite sources appropriately. Now, I'll write the article. Antenna and Wave Propagation by K.D. Prasad – A Complete Reference for Students and Professionals Structure of the ionosphere