**4. Ultra-wideband glucometer**

It is an ultra-wideband device used for measuring the glucose concentration in the blood noninvasively. The glucose concentration has been found relatively changing within the blood dielectric properties, according to the percentage of glucose that contain. Here, a decrease in the blood dielectric properties (permittivity) has been observed when the glucose percentage was increased (inverse relationship). This decrease was appeared clearly when the frequency range is increased and remained almost constant when it passed the 5GHz as shown as in **Figure 8**. Although, other factors may have an effect on the dielectric properties like temperature, gender, clotting rate, and blood density. This method can be applied accurately by using one ultra-wideband transceiver that is attached to the superficial blood vessel, and then compares the sent and the received signals which have been detected by the same transceiver to calculate the reflection coefficient. The proposed device will be depending on the reflected waves from the blood for measuring the glucose concentration, where a Vivaldi UWB antenna has been attached to the superficial blood vessels to detect the reflection coefficient. The reflection coefficient (Γ) can be obtained from the comparison between the amplitude of transmitted and received (reflected) waves [44]:

$$E\_r = \Gamma . E\_i \tag{23}$$

where *Ei* is the incident wave and *Er* is the reflected wave. Also, the reflection coefficient has proportional relationship with the blood permittivity (Ԑr) as illustrated below:

$$
\Gamma = \frac{\sqrt{\varepsilon\_{r1}} - \sqrt{\varepsilon\_{r2}}}{\sqrt{\varepsilon\_{r1}} + \sqrt{\varepsilon\_{r2}}} \tag{24}
$$

Finally, the blood glucose concentration has been measured with high percentage of accuracy, which is related to the changes in the blood permittivity (dielectric properties).

## **5. Conclusions**

The finding of the results and hypothesis in Section 3 have concluded a selective direction ultra-wideband imaging radar with multi-static used for angiography with many features; the most important features for this radar are minimizing the power dispersion to the half, which is causing decrease in the attenuation of the signal at
