Since the substrate integrated nonradiative dielectric(SINRD)waveguide fabricated directly on printed circuit boards(PCBs)was proposed

it has been a key issue how to excite the SINRD waveguide by using a planar structure.This paper presents a novel planar transition of the SINRD waveguide.The transition first uses a transition structure from microstrip to slotline.After that

since the field distribution of quasi-TEM mode of a slotline is similar to that of SINRD waveguide LSM

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mode

the main mode LSM

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of SINRD waveguide can be excited very well.By using multi-structure

two Arlon TC600 boards with different heights

t

he transition from microstrip to slotline can be directly fabricated on the thinner board.In this way

the good performance of the transition from microstrip to slotline can be achieved while the slotline is located almost in the middle of the dielectric strip of SINRD waveguide therefore can be used to excite the SINRD waveguide.It means that wider bandwidth and higher integration can be obtained.The simulation results and measurement data verify the novel transition.