# Triple-Band Notched Ultra-Wideband Microstrip MIMO Antenna with Bluetooth Band
## 2 Design of an Ultra-Wideband Antenna Element
### Step 4: UWB Antenna with Triple Notch at WiMAX Band, WLAN Band, and X-Band (Proposed)  
The final step in designing the proposed UWB antenna element with a triple band notch is to design a third band notch for X-band satellite communication that operates from 7.9 to 8.4 GHz. The X-band satellite communication band notch is required to be taken into account to overcome the interference between the obtained FCC-UWB signal and the X-band satellite signal. Electromagnetic band gap structure (EBG) technology is introduced to design a band stop filter to reject the licensed X-band satellite communication band over the aforementioned frequency range. A frame composed of an octagon-shaped EBG was proposed to achieve a band notch characteristic at X-band satellite communication in the UWB antenna, as shown in Figure 10, right view. Two identical frames of octagon-shaped EBG are placed along the 50-ohm feeding line with a vertically separated distance of a quarter wavelength (\(\lambda_{g}/4\)). The frame of the octagon-shaped EBG is connected to the metallic via (i.e., shorting pin) by using two vertically microstrip ties. The metallic via connects the octagon-shaped EBG to the ground plane. Placing two EBG unit cells with a separated distance of a quarter wavelength introduces a high sharpness edge at both the beginning and the end of the X-band satellite communication notch band. The horizontal  
Figure 8: Simulation reflection coefficients for UWB antenna with dual-band notch.  
Figure 9: The parametric study of the length \(L_{\textit{SWLAN}}\).  
length (\(I_{E2}\)) and the vertical length (\(I_{E3}\)) of the EBG unit represent important parameters in adjusting the required stop-band characteristics. Figure 11 shows the investigation of the effect of \(L_{E2}\) and \(L_{E3}\). The two lengths \(L_{E2}\) and \(L_{E3}\) are equal in value. Three values of \(L_{E2}\) and \(L_{E3}\) are selected, 2.74 mm, 3.24 mm, and 3.74 mm, while the other parameters are kept constant. It is clear from Figure 11 that the optimum curve is at \(L_{E2}=L_{E3}\) = 3.24 mm. Figure 12 shows the simulated reflection coefficient (\(\mid S_{11}\mid\) in dB) of the proposed UWB antenna with triple band notches at the WiMAX band, WLAN band, and X-band. It is shown in Figure 12 that the proposed UWB antenna operates from 2.03 GHz up to 15.04 GHz. The proposed antenna rejects triple bands, namely the WiMAX band (from 3.28 GHz to 3.8 GHz), WLAN band (from 5.05 GHz to 5.9 GHz), and X-band (from 7.78 GHz to 8.51 GHz). The proposed antenna supports the Bluetooth frequency that operates from 2.4 to 2.483 GHz. Moreover, it is observed that the X-band notch is located between two sharp edges. One is located at the beginning of the X-band notch and the other is located at the end of the X-band at frequencies of \(f\) = 7.29 GHz and \(f\) = 8.59 GHz, respectively. Adding the Bluetooth band to the UWB signal is very useful for establishing a communication channel between unlicensed bands for users/patients and diagnostic devices in biomedical applications.