Search

To meet the anti-interference and multi-function requirements of the antenna, a compact 8-states frequency reconfigurable ultra-wideband (UWB) monopole antenna is proposed. The antenna consists of a coplanar waveguide structure (CPW), defected ground structure (DGS), rectangular radiation patch, and stepped feed line. Band rejections at the C band, WLAN, and X band are generated by two C-slots and inverted U-slot, respectively. Three PIN diodes are connected across the C-slots and inverted U-slot. By controlling the on/off state of PIN diodes to realize notch reconfiguration. The antenna size is only 22 mm $\times 13$ mm $\times0.8$ mm. The measured results show that the antenna can work in 8 states. The impedance bandwidth of UWB mode is 2.82-13.25 GHz, the relative bandwidth is 129.8%. The notch band is 3.19-4.58 GHz, 5.26-6.21 GHz, and 7.87-8.73 GHz, respectively. The antenna has stable gain, good omnidirectional radiation performance, and can switch freely between UWB mode and each notch band mode.

In this letter, a probe-fed reconfigurable dual-/triple-band circularly polarized (CP) Spidron fractal dielectric resonator antenna (SFDRA) is proposed. Initially, a dual-band CP SFDRA is designed. An eigen-mode simulation of an isolated SFDR concludes that the quasi-TM $_{11\delta }$ and quasi-TM $_{21\delta }$ are excited in the lower band, whereas the quasi-TE $_{12\delta }$ mode is excited in the upper CP band. The modes of the lower CP band are separated by etching a T-shaped slot from the ground plane, thereby achieving overall triple-band circular polarization. In addition, the TSS being $\lambda _g/2$ in length at 2.64 GHz produces a band-notch function. CP band reconfigurability is attained by placing a diode D1 across the width of the TSS such that the on-/off-state of the D1 radiates dual-/triple-band CP waves. The measurement results in the on-[off]-state show the impedance bandwidths for $\mathopen |$ $S_{11}\mathclose |< $ $-$ 10 dB of 57.60% (2.2–3.98 GHz) [14.44% (2.12–2.45) and 40.48% (2.64–3.98 GHz)] and the 3 dB axial-ratio bandwidths of 24% (2.31–2.94 GHz) and 6.82% (3.68–3.94 GHz) [6.34% (2.29–2.44 GHz), 6.65% (2.76–2.95) and 7.09% (3.67–3.94 GHz)] in an ascending order of the frequency. A reasonable match is observed between the simulated and experimental data. [ABSTRACT FROM AUTHOR]