[Amps] Stripline design

[John Lyles]

Paul
There are some pretty decent texts and articles that may help you grasp stripline and coaxial amplifier circuits, if you'd like to know more than just cutting and trying approach. The west coast Radio Handbooks by Bill Orr, W6SAI, were especially good in this regard, from 20th edition up. He worked at Eimac with Sutherland and other high power amplifier experts there. Chapter 8 of the ARRL UHF/Microwave Experimenters Manual, and older RSGB VHF/UHF manual are also resources. One particular series of articles in Ham Radio magazine by H. Meyer, W6GGV, tweaked my interest and really gave me a better understanding of the various methods of making transmission lines and using them to match tubes in amplifier circuits at very high frequencies and above. The dates of these articles, "Transmission Line Circuit Design", were Nov. 1980, Jan. 1981, Feb. 1981, March 1981 and April 1981. These magazines may be available on CD or download these days. 
It's a really interesting aspect of radio design, where distributed circuits kick in, along with using lumped element approximations. Good luck, and remember, your GDO and a network analyzer are your best friends in this regime. 
73
John K5PRO

> I've had a casual interest in how striplines work for a while, but not to the point that I have started a detailed study.  You've provied a great explanation.  From what I  can gather, the "stripline" is just being used in the same way as for example a coaxial transformer.  The difference is "we" are creating the coax out of the equipment case and the bar connected to the tube anode.  Based on the bar size and the case size, the impedance is determined.   This seems very similar in idea to calculating impedance of a coax cable by using the 138log(D/d) equation.  If this is roughly true, then increasing the strip size, thereby reducing the distance between the strip and the case will make the impedance lower, this would be the case of extending the strip on one end.