Design of Cross-Coupled Bandpass Filters with Flexible Coupling via Half-Mode Substrate-Integrated Waveguide

Table 1

Comparison with other reported SIW BPFs.

Ref.	Technique	Negative coupling	Additional coupling structure	Layers	Np	Nz	(GHz)	FBW (%)	IL (dB)	Size ()	Profile ()
[6]	SIW+shorted CPW	Y	N	1	5	4	7.5	5.2	2.2	1.09	0.025
[7]	SIW+SIGCPW	Y	Y	1	3	2	9.96	4.07	1.64	1.25	0.025
[13]	SIW+HMSIW	N	N	1	3/3	2	5/7.5	5.46/4.75	1.65/2.25	1.53	0.014
	HMSIW	Y	Y		4/4	4	5/8.5	6.26/7.75	2.02/1.82	1.10	0.016
[19]	SIW+CRLH+meander-line	N	N	1	5	2	10.14	12.9	0.91	0.63	0.025
[21]	Multimode circular SIW	N	Y	1	5/5	4	46.7/60	11.7/6.8	2/2.8	2.91	—
[22]	Multimode folded SIW	N	N	2	3	3	10.18	3.2	2.33	0.76	0.026
					2/2	4	8.71/10.1	1.9/2.7	2.8/1.98	0.76	0.022
					4	4	10.08	4.5	1.82	0.77	0.025
[32]	Multimode HMSIW	N	Y	1	4	4	10	5.3	2.4	1.75	0.025
[33]	Multimode SIW	N	N	1	5	2	10	3.5	2.04	3.77	0.025
This work	SIW+HMSIW	Y	N	1	3	1	4.90	14.48	1.22	0.94	0.016
						1	5.06	12.65	1.92	0.93
	Dual-mode SIW+dual-mode HMSIW				3/3	6	5.02/7.85	15.84/20.64	1.34/1.47	1.11

: center frequency; FBW: fractional bandwidth; IL: insertion loss; Np: number of transmission poles; Nz: number of TZs; Layers: number of substrate layers; : guided wavelength in the dielectric substrate at the center frequency of the passband or the first passband of the multiband.