Research Article
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 ( = 10.2) = 0.762 mm | RO4003 ( = 3.38) = 0.508 mm |
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