Ultra-Compact and Wideband V(U)HF 3-dB Power Dividers Consisting of Novel Asymmetric Impedance Transformers

Novel asymmetric impedance transformer (NAIT) containing most of symmetric and asymmetric impedance transformers' properties is proposed for ultra-compact and wideband 3-dB power dividers. All the simulated frequency responses of the NAITs are about the same, regardless of sizes, which is regarded as one of the distinct and unique properties not only for the size reduction with design flexibility but also for the wide bandwidths, considering that the bandwidths of the general passive components are proportional to the sizes. The advantage of the NAITs can also be confirmed by another example that even if the NAIT is three times shorter than the previous one, slightly wider bandwidth can be achieved. To verify the suggested theory, one NAIT power divider is tested at 100 MHz. The total transmission-line sections (TLs) of the power divider are only 14.6° long, and the measured bandwidth is about 58 %, leading to 99.3 % size reduction, compared to the conventional typical ones with 90° TLs. In terms of sizes versus bandwidths, the fabricated NAIT power divider may be regarded as the smallest among those ever recorded, based on the low-cost microstrip technology.