A Novel Integrated Power Module with Solid-State …
3
2 Conceptual Visualization of the Integrated Power Module
To visualize the concept, we first need to know some details of resonant-cap oscillator, broad banding with slotted-disc structure and microstrip patch antenna and the
IMPATT diode as all the three has been combined in an improvised way to realize
the integrated power module.
2.1 Resonant-Cap Oscillator
Oscillator design at microwave and millimetre-wave frequency can be done by
mounting the active device, for example, solid-state devices like IMPATT or Gunn,
in a waveguide either via a bias-post or a resonant-cap structure, vide Fig. 2 [14].
The problem of mounting the device in a full-height waveguide with bias-post is
that impedance matching between the device and the circuit is very poor (device
impedance << circuit impedance); thus, the power output that can be realized is
quite low. However, if the diode is mounted in a reduced-height waveguide, then
the impedance matching between the device and the circuit is improved (as the
reduction of waveguide height lowers its characteristic impedance significantly).
But in such a case, we need to match the impedance of the reduced-height waveguide with the full-height waveguide either with a stepped-impedance transformer or
Fig. 2 Different types of IMPATT/Gunn oscillator configuration a Bias-post in full-height
waveguide b Reduced-height waveguide with stepped/exponential tapered transformer c Coaxialwaveguide-type cavity d Resonant-cap in full-height waveguide
3
2 Conceptual Visualization of the Integrated Power Module
To visualize the concept, we first need to know some details of resonant-cap oscillator, broad banding with slotted-disc structure and microstrip patch antenna and the
IMPATT diode as all the three has been combined in an improvised way to realize
the integrated power module.
2.1 Resonant-Cap Oscillator
Oscillator design at microwave and millimetre-wave frequency can be done by
mounting the active device, for example, solid-state devices like IMPATT or Gunn,
in a waveguide either via a bias-post or a resonant-cap structure, vide Fig. 2 [14].
The problem of mounting the device in a full-height waveguide with bias-post is
that impedance matching between the device and the circuit is very poor (device
impedance << circuit impedance); thus, the power output that can be realized is
quite low. However, if the diode is mounted in a reduced-height waveguide, then
the impedance matching between the device and the circuit is improved (as the
reduction of waveguide height lowers its characteristic impedance significantly).
But in such a case, we need to match the impedance of the reduced-height waveguide with the full-height waveguide either with a stepped-impedance transformer or
Fig. 2 Different types of IMPATT/Gunn oscillator configuration a Bias-post in full-height
waveguide b Reduced-height waveguide with stepped/exponential tapered transformer c Coaxialwaveguide-type cavity d Resonant-cap in full-height waveguide