Coupled‐line 180° hybrid coupler

Abstract

segments, which is connected to the corner segment, should be modified. Hence, an additional parameter ␣ (0 Ͻ ␣ Ͻ 1) was introduced to represent this variation of the inductancee. That is, the inductance L s in the second ⌸-network of straight segment 1, L s in both of the two ⌸-networks of straight segment 2, and L s in the first ⌸-network of straight segment 3 were multiplied by factor ␣. As for the shunt blocks of the straight-line segments, the influences of the corner can be omitted; thus, the parameters were kept unchanged. RESULTS, DISCUSSION AND VERIFICATIONBased on the S-parameter measurements and the modified model, the circuit parameters and the multiplication factor ␣ were extracted, as listed in Tables 1 and 2.From Table 1, the properties of the corner segments can be derived as follows: For the right-angled bends, the areas of the corner segments under test are 1.5 ϫ 1.5 m, 5 ϫ 5 m, and 10 ϫ 10 m. The corner segment with a larger geometrical dimension has a larger series inductance and a larger substrate capacitance. While its series resistance and substrate resistance are smaller. For the 45°bends, the same trends can be observed.From Table 2, it is observed that the multiplication factor ␣ is always smaller than 1, as expected according to the previous section.In , the simulated S-parameters based on our model for 90°and 45°bends are compared with the corresponding measurement results. Due to the symmetry of the test structures, that is, S 11 ϭ S 22 and S 12 ϭ S 21 , only S 11 and S 12 were compared. Magnitudes and phases were plotted separately.From the illustrated graphs, there is satisfactory agreement between the simulation results and the measurement data over the whole frequency range under consideration. The average error is less than 5%. At this point, the validity of our constructed model has been demonstrated. This suggests that the modified equivalentcircuit model can characterize the properties of on-wafer interconnects with bends up to 20 GHz, which is adequate for RF applications. SUMMARYIn this paper, an improved equivalent-circuit model for RF interconnect bends has been constructed. The accuracy of the model was verified up to 20 GHz. This simple but accurate model can be implemented into conventional circuit simulators as a subcircuit prototype.

Novel Coupled Line 180<formula formulatype="inline"> <tex Notation="TeX">$^{\circ}$</tex></formula> Hybrid With Non-Interspersed Input and Output Ports

“…Finally, , , pF, and pF. By using the ADS circuit simulator, the characteristics of the two proposed hybrids are compared with the hybrid in [32] and the classic rat-race hybrid, as shown in Fig. 8.…”

“…Fig. 8(a) shows that the rat-race hybrid has the widest bandwidth for amplitude imbalance, and the hybrid in [32] occupies wider bandwidth than the two proposed hybrids. The proposed hybrid with has the narrowest bandwidth for amplitude imbalance, while the bandwidth for amplitude imbalance of the case is wider than that of the case.…”

“…The proposed hybrid with has the narrowest bandwidth for amplitude imbalance, while the bandwidth for amplitude imbalance of the case is wider than that of the case. Due to the use of the TRD coupler, the two proposed hybrids have a slower changing region of phase difference from 2.0 to 2.8 GHz than the hybrid in [32], as depicted in Fig. 8(b) and (c).…”

“…Later on, non-TEM couplers [29], [30] and near-TEM Lange couplers [31] are used to construct the non-interspersed input/output ports 180 hybrid on the basis of the microstrip coupled line structure [32]. Fig.…”

“…Fig. 1 shows the electrical schematic of the microstrip coupled line 180 hybrid proposed in [32]. It is comprised of two identical parallel coupled line couplers.…”