Design of a Microwave Quadrature Hybrid Coupler with Harmonic Suppression Using Artificial Neural Networks

Table 3

Performance summary of the presented coupler and similar works.

Refs.	Frequency (GHz)	Harmonics suppression	Isolation (dB)	Return loss (dB)	Insertion loss (dB)	Type	Applied technique
[8]	1	2^nd to 5^th	19	18	0.2	Coupler	Open ended resonator
[48]	1.8	2^nd and 3^rd	20	20	0.6	Power divider	EBG
[49]	1	3^rd to 5^th	30	30	0.2	Power divider	Capacitor loading
[50]	2.4	2^nd and 3^rd	20	22	0.65	Power divider	Spiral resonant cell
[51]	0.9	3^rd	NA	36	0.325	Power divider	Complementary split ring resonator
[52]	1	2^nd to 4^th	32	40	0.25	Power divider	Controllable transmission zeros
[53]	1	—	25	20	0.5	Coupler	Fractal resonators
[54]	26	—	11	11	1	Coupler	Dielectric constant
[55]	0.9	2^nd and 3^rd	28	28	0.3	Coupler	Open stubs
[56]	0.9	3^rd and 5^th	31	36	0.3	Coupler	Resonant cell
[57]	3	2^nd to 4^th	23	23	0.4	Coupler	Nonuniform lines
This work	1	3^rd to 14^th	22.5	21	0.4	Coupler	Elliptic filter and ANN