Low loss compact meander stripline delay lines using LTCC

Ultra-low loss compact delay lines with grid ground stripline structure are proposed. The loss is less than full metal ground stripline. These delay lines are half loss(0.4dB/ns) and 59.5% size(214mm3/ns) compared to commercial product D20 series of EMC Tech. The self-interference canceling circuits of 4G(the 4th generation mobile communication system) base station running at co-frequency, real-time full duplex mode need ultra-low loss and compact delay lines. The ultra-low loss is especially desired. Otherwise, too much energy are injected from transmitter power amplifier(PA) to self-interference canceling circuits, and the efficiency of PA will decrease obviously. Both performance requests are satisfied by the delay lines this paper proposed.