Table 2 Comparison of the proposed antennas and reference antennas.

Antenna type

Horn

Waveguide

Horn

Planar

MTM

Dual band operation

Yes

Yes

Yes

Yes

Yes

Filtering response

No

No

Yes

Yes

Yes

Conical beam

Yes

Yes

Yes

No

Yes

Central freq. (GHz)

10/35

28/38.5

24.7/33.8

3.45/5

3/4.3

OBGSL (dB)

N/A

N/A

No data

18.1/17.7

30/32

Null depth (dB)

 − 25 to − 30*

 − 25 to − 30*

 − 18 to − 30*

N/A

 − 22 to − 50

Volume (\({\lambda }_{1}^{3}\))

1.7 × 1.7 × 1*

0.7 × 0.7 × 24.5**

2.78 × 2.45 × 3.03

0.75 × 0.75 × 0.13

0.8 × 0.8 × 1.4

Volume (\({\lambda }_{2}^{3}\))

6 × 6 × 3.5**

1 × 1 × 33**

3.8 × 3.4 × 4.1**

1.1 × 1.1 × 0.18**

1.15 × 1.15 × 2

Gain (dBi)

9.2/11.6

14.5/14.2

8.8/6.4

8.5/9

2.8/4.5

Efficiency (%)

N/A

83–90

 > 83

 > 90

 ~ 83