EBG assisted reconfigurable phased array
antenna is investigated applicable for dual-band operations. With a view to
achieving dual-band operation another set of 4 antennas is connected with
shorter resonant length (lg/4 that
is 1/4th wavelength).
4 patches connected with the feed networks are
known as active patches. Shorter 4 patches will be connected by PIN diode and
they are known as dummy or parasitic patches. Dummy patches are connected with
the active patches with associated biasing networks. During the forward bias
condition of PIN diodes, total patch length increases as the patch length of
the active and dummy patches are added. Over all patches resonate at lower
frequency. During the reverse biased condition the resonant frequency
corresponds to the length of active patches. Thus controlling the bias
condition of diodes, dual band operations of antennas are achieved. To have a
clear idea on the design to reconfigure the frequencies of operations one side
connection of a 4 elements array is shown. One dummy patch needs two PIN diodes
to be connected with one active patch. One 4 elements array requires total 8
PIN diodes. So there are total 8 biasing networks to control 8 PIN diodes. One
sample connection of patches with biasing network is shown in Fig. 7.25.
EBG assisted reconfigurable phased array
antenna is investigated applicable for dual-band operations. With a view to
achieving dual-band operation another set of 4 antennas is connected with
shorter resonant length (lg/4 that
is 1/4th wavelength). 4 patches connected with the feed networks are
known as active patches. Shorter 4 patches will be connected by PIN diode and
they are known as dummy or parasitic patches. Dummy patches are connected with
the active patches with associated biasing networks. During the forward bias
condition of PIN diodes, total patch length increases as the patch length of
the active and dummy patches are added. Over all patches resonate at lower
frequency. During the reverse biased condition the resonant frequency
corresponds to the length of active patches. Thus controlling the bias
condition of diodes, dual band operations of antennas are achieved. To have a
clear idea on the design to reconfigure the frequencies of operations one side
connection of a 4 elements array is shown. One dummy patch needs two PIN diodes
to be connected with one active patch. One 4 elements array requires total 8
PIN diodes. So there are total 8 biasing networks to control 8 PIN diodes. One
sample connection of patches with biasing network is shown in Fig. 7.25.
Fig. 7.25: Geometry of reconfigurable patches with associated
biasing networks to control PIN diodes (only one connection has been shown).
Biasing networks consist of LC tuning
circuit, filtering and DC blocking capacitors. There is also a current limiting
resistor. The feed network of a PBG assisted phased array antenna is designed
with the distribution of square patterned PBGSs as 0-8-16-24 having FF of 0.5.
The length and width of the active patches are 11.075 mm and 11.425 mm
respectively. To achieve dual-band operation another set of 4 elements dummy
patches is used. The length of the dummy patch is 6.019 mm having same width.
The connections of current limiting
resistors and voltage supplies are transferred to the ground plane for the
minimum perturbation of the patch layer. It is shown in Fig. 7.25. Due to
unavailability of X-band RF diodes conductive copper tape is connected with the
active patches. The conducting copper tape has the same dimensions of dummy
patches.
Fig. 7.25: Geometry of reconfigurable patches with associated
biasing networks to control PIN diodes (only one connection has been shown).
Biasing networks consist of LC tuning
circuit, filtering and DC blocking capacitors. There is also a current limiting
resistor. The feed network of a PBG assisted phased array antenna is designed
with the distribution of square patterned PBGSs as 0-8-16-24 having FF of 0.5.
The length and width of the active patches are 11.075 mm and 11.425 mm
respectively. To achieve dual-band operation another set of 4 elements dummy
patches is used. The length of the dummy patch is 6.019 mm having same width.
The connections of current limiting
resistors and voltage supplies are transferred to the ground plane for the
minimum perturbation of the patch layer. It is shown in Fig. 7.25. Due to
unavailability of X-band RF diodes conductive copper tape is connected with the
active patches. The conducting copper tape has the same dimensions of dummy
patches.
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