| Title | 
	[REGULAR PAPER] An Integrated Low-loss Lumped-element Quadrature Coupler Using a Distributed Model  | 
					
	| Authors | 
	(Hyunjin Ahn) ; (Ilku Nam) ; (Dong-Ho Lee) ; (Ockgoo Lee) | 
					
	| DOI | 
	https://doi.org/10.5573/JSTS.2020.20.3.249 | 
					
	| Keywords | 
	 Modeling; lumped-element; on-chip; quadrature coupler | 
					
	| Abstract | 
	This paper presents a distributed model of a lumped-element quadrature coupler that accounts for the distributed nature of parasitic elements. The required capacitors in the constitution of lumped-element quadrature couplers can be properly considered using the proposed distributed model. An integrated low loss lumped-element quadrature coupler is implemented using the proposed model. The modeled responses are compared with the corresponding measured responses; they exhibit good agreement. The measured insertion loss for both direct and coupled ports is 3.23 dB at 5.5 GHz. The variation in the insertion loss is ± 0.3 dB with a phase imbalance of less than 0.95° across a 760-MHz bandwidth.  |