At low input power levels, the peak amplifier is cut off because of the class C operating condition The output impedance [Z.sub.p] of peak cell, should present an open circuit state in theory to prevent power leakage by tuning the offset line [theta]p between peak amplifier and quarter-wave line
. The output impedance [Z.sub.C] of carrier cell is now equal to [Z.sub.1].
The input signal is split with a Wilkinson divider and a 50 [ohm] quarter-wave line
is inserted in the input stage of the peaking amplifier to match the delay between the two paths.
The ability to control the line length (for what would otherwise be a series of fixed-length quarter-wave lines
) adds important new design flexibility.
The fabricated hybrid demonstrates good design accuracy resulting in a circuit with a miniature size of [lambda]/24 instead of quarter-wave lines.
Power dividers using quarter-wave lines become prohibitively large at the lower frequencies and result in MMIG chips of larger size and higher cost.
The measured input for each winding was 28 [omega] within the frequency band of interest, so a matching network of four 37 [omega] quarter-wave lines
was incorporated to match the antenna to a 50 [omega] input.
This section may be made wider band by adding stages or additional resistors with quarter-wave lines separating each one.
Key features to note are the larger than 50 [Omega] line width ([w..sub.50] = 0.0175[inches]) and the shorter than quarter-wave lines ([Lambda]/4: 0.172[inches]).
The theory calls for shorted quarter-wave lines
closely coupled together.