Electrically Tunable Diode-Based Nonlinear Transmission Line

Diode-based nonlinear transmission lines (D-NLTLs) are capable of generating pulsed radio frequency (RF) signals with center frequency (
$f_{c}$
) in the ones-of-GHz range and volumetric power densities (
$\rho _{v}$
) on the single GW/cm3. However, the use of monopolar excitation signals limits the
$f_{c}$
range and incurs impedance losses that reduce
$\rho _{v}$
. To mitigate this issue, a direct current (dc) bias was used to create an effective bipolar input, reducing impedance losses, resulting in a 37% increase in
$f_{c}$
and a
$4\times $
improvement in
$\rho _{v}$
compared to the unbiased case. Observed increases in
$f_{c}$
and
$\rho _{v}$
are attributed to a
$2.67\times $
increase in voltage amplitude measured after the connection between the pulsed source and D-NLTL over that of a monopolar pulse, which is attributed to increased diode saturation. Additionally, the effects of a dc bias on network impedance are demonstrated through electrical tuning of
$f_{c}$
over a range of 160–260 MHz with monopolar excitation signals. Overall, results indicate a dc bias can enable
$f_{c}$
modulation, increase
$f_{c}$
and
$\rho _{v}$
range and ceiling, and reduce impedance losses in a D-NLTL network.