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105 | Abdulzahra, Alnahwi & Abdullah

Fig. 6. The equivalent circuit of the PIN diode (a) OFF-state
(b) ON- state.

TABLE II.
The optimized parameters of the proposed antenna.

Parameter Dimension (mm) Parameter Dimension (mm)
19 Wf 3
Ws 26 Lc 4
Ls 9.5 Wc 4.5
Lg 11 d 3
Wp 9 g 0.5
Lp 12.5 r 1
Lf

Figures 13 and 14 depict the antenna simulated normalized Fig. 7. (a) The effect of slit width at ON-state (b) The effect
power patterns at OFF-state and ON-state of the PIN diode, of slit length at ON-state.
respectively. It is clear that the power pattern of the antenna
is omnidirectional for both states of the PIN diode, which when the switch is turned OFF. Meanwhile, the antenna op-
is preferable for IoT portable devices since this pattern is erates at wideband mode when the PIN diode at its ON-state.
location independent. The wideband mode has a peak value of the realized gain of
1.57 dBi with an omnidirectional power pattern, while the
Fig. 15 (a) and (b) depicts the simulated gain responses peak gain of the dual-band mode is 0.85 dBi with omnidi-
for the dual-band mode and the wideband mode,respectively. rectional power pattern too. These results make the antenna
For dual-band mode, the peak value of the simulated gain is very compatible with the IoT portable WIMAX and WLAN
0.86 dBi at 3 GHz and 0.47 dBi at 6 GHz, while the peak gain devices. The proposed antenna has numerous advantages
is 1.57 dBi for the wideband mode. As long as the gain values including its small size, low cost, and simple configuration,
are larger than 0dB, the antenna radiation characteristics are which make it suitable for integrated with any IoT gadgets.
acceptable for short range applications [21].
CONFLICT OF INTEREST
It is important to note that, despite the antenna small
size, the gain value is perfect and extremely beneficial for The authors have no conflict of relevant interest to this
IoT applications. The characteristics of the proposed antenna article.
structure are compared to those of some previous frequency
reconfigurable antennas in Table III. The table makes it abun- REFERENCES
dantly clear that the proposed antenna has excellent radiation
performance, a wide bandwidth in spite of its compact size [1] D. E. Anagnostou, M. Chryssomallis, and S. Goudos,
compared to the other antennas. “Reconfigurable antennas,” Electronics, vol. 10, no. 8,
p. 897, 2021.
VI. CONCLUSION

A compact frequency-reconfigurable antenna with dual-
band and wideband operational modes is designed in this
paper. The structure of the antenna patch is modified in accor-
dance with the PIN diode ON and OFF states. The presented
antenna covers dual frequency bands of 3GHz and 6 GHz