Codesigned Wideband High-Efficiency Filtering SIW Slot Antenna with High Selectivity and Flat Gain Response

Table 1

Comparisons with previous reported works.

Ref	Number of Pole	Number of Null	BW (%)	Selectivity (dB/GHz)	Eff. (%)	Size ()	Layer
[8]	4	0	6	113/74	89	1.3 × 1.7	1
[9]	2	0	3	63/28	58.9	0.9 × 0.9	2
[10]	3	2	1.6	96/55	86	0.7 × 0.9	3
[11]	3	0	5.5	26/57	N.A.	1.4 × 1.6	2
Ours	3	2	9.1	270/330	93	1.1 × 1.2	1

is the guide wavelength at the centre frequency of the work band. Selectivity is calculated as , where is the attenuation of the first out-of-band radiation null or 20 dB attenuation if no radiation null and is the 3 dB attenuation; and are their corresponding frequency.