|
|
发表于 2014-11-4 22:38:24
|
显示全部楼层
三页~ 1 Simple Microstrip Matching for all Impendances
During the evaluation of new devices, it is often difficult to find a simple matching circuit to a 50 Ω impedance.
In a 50 Ω coax fixture this can be achieved by adjusting two slide screw tuners, which apply a movable variable
capacitance to a triplate line.
In a practical application, matching is often performed using printed microstrip lines. Such layouts often require a
large amount of effort in design and simulation to reach a solution. This effort can be reduced by using a simple
“universal printed circuit board”, which can realise all transformations to the device under test. Such a “universal
printed circuit board” is presented below.
1.1 Realisation
A universal printed circuit board consists of two straight 50 Ω lines at the input and output of the device under test,
with an electrical length of at least λ/2 at operating frequency.
Alongside these λ/2 lines sufficient space is left for movable λ/4 open stub lines.
Biasing can be provided by small λ/4- lines on the board as shown below, or through external bias tees.
Figure 1 Universal printed circuit board
Using such a universal printed circuit board it is possible to match all (!) impedances to 50 Ω by applying movable
open 50 Ω stubs with variable length. The stubs can be made from strips of copper or brass foil which can be
moved along the input and output lines using a soldering iron and cut in length. If they become too short, they can
be simply replaced by new strips. The width of these strips determines the impedance and should therefore be the
same as the lines on the pcb.
Although this method is a simple cut and try stra还有两页广告 |
|
/2 
eetop公众号
创芯大讲堂
创芯人才网
发表于 2014-11-7 17:35:45
