The DC-DC coupler is a product concept put forward by china unicom first Because the common passive directional coupler can not pass DC at all ports, for some DAS or inbuilding wireless coverage may need DC supply,so vinncom design series air-dielectric directional couplers for DC pass at all ports. 550-2700MHz,550-3800MHz,698-4000MHz with 3~30dB coupling and N female\4.3-10female or other RF connectors.Also we got patents in 2008 .

Same side inputs and same side outputs Air dielectric 3dB Hybrid is a product developed by our company in cooperation with comba in 2006.
The input and output of the device are in the same side, which makes the engineering installation more convenient. On the basis of Low PIM research and development, our company has developed series 3dB hybrid products with different frequencies for market , and this series of products is used in all distributed antenna systems. And got related patents in 2007 ,vinncom also participated the draft of  the standards for china mobile for this series 3dB hybrid coupler together with comba .