Compact Microwave Components with Harmonic Suppression Based on Artificial Transmission Lines

Table 4

Performance comparisons of branch-line couplers.

Ref	Central frequency (GHz)	Size	-15 dB BW (%)	At central frequency			Harmonic suppression (dB)
				(dB)	, (dB)	(dB)	Second-order harmonic	Third-order harmonic
[19]	0.91		8.9	33	3.2, 3.7	40	No suppression	No suppression
[20]	0.9		18.9	30	3.36, 3.25	22	No suppression	No suppression
[21]	0.8365		7.2	25	3.9, 3.9	28.9	20	No given
[22]	0.875		19.4	35	2.94, 3.72	43	5	5
[27]	1		20	34	3.5, 3.6	30	No suppression	No suppression
[28]	1.675		23.2	35.1	2.8, 3.15	34.1	No suppression	No suppression
This work	0.91		17	29.35	3.2, 3.15	26.3	12.6	29.5

: guided wavelength at central frequency.