In this work, a printed ultra-wideband (UWB) antenna has been proposed exhibiting band notch characteristics. The proposed design covers the entire UWB band except for the 3.5 GHz band providing the band notch for the WiMAX band. This design consists of two-quarter elliptical patches placed symmetrically over the FR4 substrate. The elliptical shape of the patch is responsible for the UWB band achieved. The slot has been created on the optimized patch area to achieve the desired characteristics providing a notch for the WiMAX band. The slot in the patch is so perfectly designed that it gives the patch a perfect shape of butterfly wings. After designing, the proposed antenna was simulated and then fabricated. The fabricated and simulated results are in close agreement with each other which shows, the proposed UWB antenna is good enough for biomedical applications.

This research paper introduces a ultra-wideband (UWB) multiple input multiple output (MIMO)/diversity antenna with three rejected bands using one compact electromagnetic band gap (EBG) structure. The suggested EBG structure rejects three bands at WiMAX, WLAN, and the X-band within the passband of the UWB antenna. To achieve compactness in the conventional EBG structure, two via and square slots are introduced. This structure contributes to better impedance matching by using tapered feedline and slots in the radiating patch. To improve the isolation among all four compact UWB monopoles, decoupling strips are extended from the ground plane. Furthermore, the |S21| is below 17 dB in between the antenna elements and the envelope correlation coefficient is below 0.5, which are tolerable values within the UWB range. Furthermore, different MIMO/diversity characteristics are also discussed. An FR-4 substrate with dimensions of 38 × 45 × 1.6 mm3 is used for the fabrication of the suggested structure.

In this paper, two asymmetric co-planar waveguide (ACPW) fed circularly polarized (CP) zeroth-order resonance (ZOR) antennas (Antenna I and II) are presented using a composite right and left-handed transmission line (CRLH-TL) approach. By adding a stub on the left side of the ACPW ground and adjusting its length, circularly polarization property has been achieved in Antenna I. The simulated 3 dB axial ratio bandwidth (ARBW) of Antenna I is 1750 MHz (3.50–5.25 GHz). Next, the left side ground plane of Antenna I is further defected by etching a quarter wavelength slit to introduce a notch band (Antenna II). Antenna II has an extended 10 dB return loss bandwidth of 2200 MHz (3.28–5.48 GHz) with a band notch from 4.18–4.65 GHz that isolates the WiMAX and 5.2 GHz WLAN bands. ARBWs of 1080 and 870 MHz are achieved in the first and second band of Antenna II. The overlapping 3 dB ARBW and 10 dB return loss bandwidths of Antenna II in these two bands are 770 and 830 MHz, respectively.

A super-wideband microstrip fractal antenna is designed with miniaturized dimensions of 21 mm × 23.5 mm × 1 mm and generation of dual rejection bands for WLAN/WiMAX systems has been achieved. The triangular fractal shape slots are placed inside a circular patch and the antenna is miniaturized by using a repetition frequency resonance technique. The proposed antenna frequency range 2.6–40 GHz operates for VSWR of less than 2. Two band rejections for the frequency ranges 5.1–5.8 GHz and 3.4–3.7 GHz are created by one enhanced slot at the feed line and one split-ring resonator at the back of antenna. HFSS 3D software was used for computer simulation. The proposed antenna is fabricated on the FR4 substrate with 1 mm thickness. The measurement data show good agreement with the simulation results.

A small and compact ultra-wideband (UWB) aperture antenna with extended band-notched design is proposed. The antenna is composed of a rectangular aperture on ground plane of a printed circuit board and a fork-like exciting stub. The presented co-planar wave guide triple-fed antenna is easy to be applied with RF and microwave circuitry for low manufacturing cost. The antenna is successfully designed, implemented, and measured. A compact aperture area of 12.5 × 23 mm2 is acquired with promising performances, including broadband matched impedance and stable radiation patterns. The correlation between the mode-based field distributions and radiation patterns is discussed. Extended from the proposed antenna, one advanced band-notched (5–6 GHz) designs are also presented as a desirable feature for UWB applications.