Ultrawide Bandwidth 180^∘-Hybrid-Coupler in Planar Technology

Table 1

Comparison between planar 180°-hybrid-couplers.

Reference	Relative bandwidth B%	Center frequency 𝑓𝑐	Maximal amplitude imbalance	Maximal phase imbalance	Size [mm]	Layers
[9]	60%	2 GHz	0.2 dB	2°	—	2
[10]	69%	10.1 GHz	0.6 dB	1.0°	20×30	2
[11]	100%	4 GHz	0.4 dB	2.5°	—	1
[12]	100%	4 GHz	0.4 dB	4°	—	1
[13]	100%	6 GHz	—	—	24×35	2
This work	114%	7 GHz	0.8 dB	5°	40×50	2

Note: the values are partly estimated from figures if not explicitly given in the paper.