Smith chart impedance matching question

Thread Starter

simozz

Joined Jul 23, 2017
114
Hi,

I am preparing for the Microwaves Circuits semester and I am reviewing Smith Chart usage, so I was looking at the book by Chris Bowick - RF Circuit Design where there is an impedance matching example at page 90. It can be seen here.

For this match, the Smith Chart plot is represented in figure 4-44 also available here (I attach it as PDF also).
In the example solution, the author says:

"... The only way we can get from the impedance at point A to the impedance at point C and still fulfill this requirement is along the path shown in Fig. 4-44. ..."

So the author says that the only way to accomplish the matching is using a shunt capacitor and then a series inductor.
But as I know, the match could be also be accomplished using shunt inductor and a series capacitor.
In fact, looking at the plot, it seems it can be accomplished using the inverse path.

Why do the author says that the represented on figure 4-44 is the only way ?
Thank you in advance.
 

Attachments

Janis59

Joined Aug 21, 2017
1,232
No, ALWAYS there are two ways, at first move to right and then upward or at first upward and then at right. BUT those both differs with one may be simple and/or effective in realisation, while other is very headachey and/or lossy. Thus, generally them write correct.
 
Last edited by a moderator:

Thread Starter

simozz

Joined Jul 23, 2017
114
OK, thank you @Janis Blahins for your confirmation.
I remember that a few years ago a good Electronics Engineering Professor told me that this book is full of errors..
 

Janis59

Joined Aug 21, 2017
1,232
RE:""Professor told me that this book is full of errors""

As practically every book. Starting from old good golden time transistor catalogues where count of serious mistakes was tens or hundreds up to the just fresh physics school-books with two-three or more mistakes.
For example, as one day in the week I spend my time to roll a pearls before the piglets in certain school, I know very well the national educ ministry accredited school book for form 11 where is said that "it is worth to bold that molecule rotational and vibrational movement in contrast to translational, never creates the temperature effects" - Oh my.... why then in all sci conferences we are speaking on molecular temperature`s translational, rotational and vibrational components and how then the microwave cooker is working, huh.
Other book slightly (only for 6 zeros) miss a water capillarity coefficient, so I once shown a class why humans are not going like Christus on the surface of water, and according the calculation the perimeter of feet ought be large enough... however the fact is that must be greater than 200 meter of circle diameter, so the `water-spider foot` is too large be realistic as construction.
Other focus-pocus I got in the recommended for schools calc.problems book. It was just innocent task for form 10 about calc the distance from volcano throws the stones, I mean asymmetric ballistic calculation. Two identical tasks, one group reads velocity and calculates distance while another are given distance and calculates velocity. The pitch - one group earns 7...8...9 marks while other 2..2..3. Then I worked full staff with 5 shifts, and second shift have the same mal-success, and next again. Then I started to calculate myself - damn, one is just simple task while reciprocally it is bi-quadratic equation what at form 10 is not taught at math. So I needed to solve somehow creatively the own fault - the fault to trust the books.

Probably the best way to go around this problem is method of voting. Like that I learned in traveling and blundering in russia haotic roads. If ask one to go to right or left, probably he will run after You to say, no no comrade, go to right not to the left (while showing by hand to the left), or he will not care. Therefore always there ask the right way at least twice and go if both shows the same. If not, ask more people and vote. Probably 3 will show right, one not, then go right.
And then someone invent the gps, but too late. That boarder was closed but another much nicer boarders are opened. Yet on them gps is not needed much and sure is no helpful to avoid the struck in the pay-roads entrances made in the manner would be extremely difficult to go around by the general use road. Especially the Italians are bad about - after 300 km by the pay-line between the fences at last You get the cash-line, but none human only automates. Automates demand a special `Italiano card` - where to get it is unknown. One cash machine works with clear cash, but only coins, where damn I have a coins if Europe is full of paper banknotes. No automate about credit card. You may stay there a week and get no out. There I learned to get very close after some larger car with wagon, keep accurately some 30-40 centimeters after and You are out with no paying, but if barrier (or cops) catch, will be bad.
 
Top