Showing papers by "He Zhu published in 2014"

Ultra-wideband in-phase power divider using stepped-impedance three-line coupled structure and microstrip-to-slotline transitions

Abstract: A compact in-phase power divider utilising a stepped-impedance three-line coupled structure and microstrip-to-slotline transitions is presented. The equivalent circuit of the structure is used to predict the required dimensions for ultra-wideband performance. The length of the structure, excluding the input/output ports needed for the measurements, is around a quarter guided wavelength. The simulated and measured results for the two developed devices indicate equal in-phase power division with less than 0.1 dB and 2° amplitude and phase imbalances, respectively. The return loss at the three ports is more than 15 dB in one prototype, whereas the isolation is more than 13 dB in the other across the band from 3.1 to 10.6 GHz.

Ultra-wideband unequal in-phase power divider using three-line coupled structure

Abstract: A compact ultra-wideband in-phase power divider using a three-line coupled structure is proposed. The power division of the device depends on the coupling factors between the centreline and the two sidelines. For an enhanced isolation between the output ports, a 100 ω chip resistor is connected between the ends of the two sidelines, whereas the end of the centre line is grounded. To verify the design, a prototype with 2:1 power division was fabricated and tested. The measured results validate the ultra-wideband performance with more than 12 dB return loss, more than 13 dB isolation and <0.2 dB and 4° amplitude and phase imbalances, respectively, across the band 3.1-10.6 GHz.

Compact ultra-wideband in-phase power divider using three-line coupled structure

Abstract: A compact ultra-wideband in-phase power divider with planar structure is presented. The proposed device utilizes three-line parallel-coupled microstrip lines. To realize the required tight coupling for an ultra-wideband performance, a slotted ground is utilized underneath the coupled lines. Moreover, chip capacitors are connected between the central line and each of the side coupled lines. Both of the equivalent circuit and fill-wave electromagnetic simulations indicate that the presented device operates across the band from 3.1 to 10.6GHz, with good insertion loss, return loss and isolation.

Compact tunable crossover with wide tuning range using coupled lines

Abstract: A compact design of tunable crossover with a wide tuning range is presented. The proposed crossover structure is based on a two-section coupler interconnected with two varactors to achieve tuning frequency range from 0.6 GHz to 1.4 GHz. The overall size of the crossover is 0.12λ g ×0.02λ g (λ g is the guided wavelength at working frequency), which is much more compact than previous counterparts. An excellent return loss (more than 20 dB), insertion loss (less than 1 dB) and isolation (more than 15 dB) of the proposed crossover are verified by EM simulations.