Abstract:
In designing any type of broadband antenna, either of single or multiple elements much
of time and recourses are consumed for proper impedance matching. Impedance
matching is broadly classified into two types i) Distributed matching ii) Lumped element
matching. Firstly Distributed matching, which leads to modification of antenna geometry
itself & secondly by lumped element, which requires to use lump element i.e. capacitor
resistor or inductors to do impedance matching between load and source
This thesis introduces a hybrid technique of impedance matching with the combination of
distributed and lumped component for tactical VHF/UHF monopole/dipole antenna .The
major objective of this thesis is to reduces the antenna losses in operational bandwidth
such that antenna gain positive in most of bandwidth and VSWR to be lower than 3.
Further antenna design is feasible for portability and capable of handling high power up
to 100 watts CW.
Three antenna models for VHF, UHF, and VHF-UHF band are proposed for high power
and broad impedance bandwidth applications. For a first prototype antenna, a bandwidth
of 10:1 was achieved in VHF band antenna. The operational bandwidth of this band
antenna is 250 MHz to 1GHz. For a second prototype antenna, a bandwidth of 200 MHz
to 520 MHz was achieved in UHF band antenna with positive gain pattern throughout the
bandwidth. For a third prototype antenna, a bandwidth of 21:1 was achieved in VHFUHF
band antenna. The operational bandwidth of this band antenna is 84MHz to 890
MHz, with the positive gain pattern in most of the frequency band. The microstrip patch
antenna for UWB application from 3.1 GHz to 10.6 GHz is also proposed and simulated
Measured results of all the designed prototype antennas are reported. The result found to
be similar with simulated results
Simulation and measured result confirm our premise.
