However, as aforementioned, it remains a critical task in LNA designs to realize impedance matching
at the input port by presenting a resistive impedance (e.g., 50 [OMEGA]).
Its initial value is ~0.8, but it rapidly decreases to ~0.45, showing that the tuning process (including both the impedance matching
(loop[C]) and the resonance condition finding loop (loop[C])) are properly working.
Indeed, optimization on the parameters of the ELC unit may could further improve the bandwidth, impedance matching
, and realized gain over a wider scan angle.
By comparing the three different algorithms of reflection coefficient magnitude, the particle swarm optimization combined with simulated annealing algorithm is a new type of impedance matching
algorithm, and the reflection coefficient tends to zero to achieve impedance matching
finally, which is better than the improved particle swarm algorithm in speed.
Third Setup: General Impedance Matching
. Mechanical impedance is defined as the ratio between the amplitudes of force and speed in a vibration movement.
In order to better match the fundamental, we need to compromise on the lower frequency harmonics impedance matching
. The second and the third harmonic suppression levels are maintained at -16 to -36 dBc and -16 to -33 dBc, respectively.
The feedline is tapered for optimum impedance matching
the antenna's fractal tree patch.
And the most difficulty issue for such an antenna design lies on the fact that these variables in the antenna structure working together to determine the impedance matching
and circular polarization performance.
Stacked structures are usually used to broaden the axial-ratio (AR) bandwidth and horizontally strip feed technique in [5,6] is proposed to achieve good impedance matching
. For the single-port and double-feed antennas, modifications are not required on the radiated patch and the approach of 90[degrees] hybrid or power splitter can obtain wide AR bandwidth but has the disadvantages of complicated structure and large antenna size .
1 shows few conventional LNA for input impedance matching
. In Fig.
In the following, we simply indicate with impedance matching
the receiver design that enables the maximum power transfer.