**4. Conclusion**

In this chapter we explained about the significance of superstrate on antenna performance at millimeter wave frequencies. It is found that the size of the superstrate is critical, which is not the case in lower frequencies. Also we studied the antenna performance with different source of excitation. It is noted that superstrate technology is very good for a single patch and also for small array but not that much good for big arrays. As a conclusion, it is found that superstrate aperture antenna element / antenna array is a good candidate for wideband, high gain and high efficiency antenna design in millimetre wave range. Moreover it is easy to integrate with electronics by placing the feed on backside of the substrate where the electronic components are integrated, and the radiating aperture and superstrate (i.e. the radiation part) are on the other side.

### **5. References**

120 Wireless Communications and Networks – Recent Advances

It is noted from the study that single/small array superstrate antenna technology is very good for high gain, wide bandwidth and high efficiency, but is not suggestive for big arrays

**3. Comparison of superstrate slot coupled antenna with superstrate aperture** 

Table VI gives the comparison of the superstrate aperture antenna element or antenna array presented with slot coupled superstrate antenna element or antenna array. It is clear that superstrate aperture antenna element / antenna array give broad S11 bandwidth of 15% / 13.3% with better efficiency as compared to superstrate slot coupled antenna element / antenna array. Also the antenna size is smaller compared to the other in both the cases. I.e. superstrate aperture antenna element or antenna array gives sufficient bandwidth, gain and

> Maximum gain (measured)

Aperture 15% 13.1 79% 6 mm x 13.5 mm x

slot coupled 6.8% 14.6 76% 10 mm x 10mm x

Aperture 13.3% 16.6 74% 13 mm x 20 mm, x

slot coupled 6.7% 16 63% 16 mm x 16 mm x

Table VI. Comparison between superstrate aperture s antenna and slot coupled superstrate

In this chapter we explained about the significance of superstrate on antenna performance at millimeter wave frequencies. It is found that the size of the superstrate is critical, which is not the case in lower frequencies. Also we studied the antenna performance with different source of excitation. It is noted that superstrate technology is very good for a single patch and also for small array but not that much good for big arrays. As a conclusion, it is found that superstrate aperture antenna element / antenna array is a good candidate for wideband, high gain and high efficiency antenna design in millimetre wave range. Moreover it is easy to integrate with electronics by placing the feed on backside of the substrate where the electronic components are integrated, and the radiating aperture and

Efficiency Estimated η

Size

3.48 mm

3.48 mm

3.48 mm

3.48 mm

because of the gain go up is not upto the point but is good in terms of efficiency.

**antenna** 

efficiency for 60 GHz applications.

Return loss bandwidth (measured)

superstrate (i.e. the radiation part) are on the other side.

Antenna

Single superstrate

Single superstrate

2x2 superstrate

2x2 superstrate

**4. Conclusion** 

antenna explained in section 2.

