Balance Analysis of Microstrip-to-CPS Baluns and Its Effects on Broadband Antenna Performance

Table 1

Performance summary of the balance analysis.

Parameters	Unit	Remarks	Conventional structure [11]; (Case I)	Proposed structure; (Case II)
Balun operating bandwidth	GHz	Back-to-back	6.5–11.4	5–20
		single terminated	6.5–12.5	4–20
Amplitude imbalance	dB	7–11 GHz.	< ±2	<±0.5
		6.5–12.5 GHz	<±6
Phase imbalance	degree	7–11 GHz.	<±8	<±3
		6.5–12.5 GHz	<±20
Antenna operating bandwidth	GHz	Quasi-Yagi	8–12	8–12
		TSA	6.5–12.5	6.5–12.5
Antenna gain	dBi	Quasi-yagi	3.5–5.5	4.9–6.3
		TSA	8.3–12.7	10.7–13
Angle deviation (max. gain direction)	Degree	Quasi-yagi	±4	±4
		TSA	±7	±2
Efficiency	%	Quasi-yagi	92–96	93–96
Occupied size	mm	Quasi-yagi	13 × 20	20 × 30
		TSA	33 × 116	36 × 123
Substrate material			Duroid6010 (𝜀𝑟 = 10.2); 𝑡 = 0.762 mm	RO4003 (𝜀𝑟 = 3.38); 𝑡 = 0.508 mm