MINIATURE SMD QUADRATURE HYBRIDS FOR WIRELESS APPLICATIONS
A series of miniature three-port surface mount device (SMD) 90° hybrid couplers have been developed for wireless applications. The series currently comprises 12 individual components spanning an 824 to 5800 MHz frequency range. Each coupler has been optimized for operation in a particular wireless frequency band and utilizes simple and reliable lumped-element construction. The unique quadrature coupler design offers stripline equivalent performance at a fraction of the size of a distributed design.
W-CDMA BAND COUPLER PERFORMANCE
Fig. 1 The three-port hybrid's outline and pin configuration.
The model HQ212-80C1 quadrature coupler serves as a good example of the design and performance achieved by this series of components. This unit, designed for wideband CDMA (W-CDMA) and optimized for 2100 to 2180 MHz operation, is housed in a standard 80 style package that measures 0.31" long, 0.25" wide and 0.19" high. Figure 1 shows the physical outline and pin configuration of the coupler. Typical insertion loss is 0.15 dB and phase balance is 90° ±3°. The unit's isolation is typically 20 dB and the amplitude balance is typically better than 0.25 dB. The coupler's return loss is better than 20 dB on all three ports and power handling typically exceeds 5 W. Figure 2 shows the coupler's typical insertion loss.
Guaranteed performance specifications include a phase balance of ±5°, amplitude balance of ±0.4 dB, maximum insertion of 0.35 dB, minimum isolation of 15 dB, and a minimum return loss of 15 dB. The nominal impedance is 50 W and the unit is capable of handling a minimum of 4 W of RF power over a -40° to +85°C operating temperature range. Figures 3 and 4 show its typical isolation and return loss, respectively.
Fig. 2 Insertion loss vs. frequency.
OTHER WIRELESS MODELS
Fig. 3 Isolation vs. frequency.
Fig. 4 Return loss vs. frequency.
MINIATURE SMD QUADRATURE HYBRIDS FOR WIRELESS BANDS