Although TE0nδ mode ceramic resonators are usually used at centimeter frequencies, they have difficulty in making wide-band band-pass filters in the millimeter-wave region due to the weak coupling factors between TE0nδ mode resonators and input/output waveguides. In order to overcome such difficulty, a band-widening technique of the ceramic resonator loaded band-pass filter has been proposed. The EHnmδ modes were regarded as spurious modes so far, but it is clear that the coupling factors are larger than those of the TE0nδ modes from the results of experimental considerations in this paper. By using the EH11δ mode ceramic resonators, 5-pole, 1 dB Chebyshev ripple NRD guide band-pass filter has been fabricated for the applications to broad-band millimeter-wave communication systems at 60 GHz. The filter has great advantages such as the wide pass-band beyond 2 GHz and low excess insertion loss of less than 0.3 dB.

An NRD guide transmitter and a receiver were developed for a wireless multi-channel TV-signal distribution system at 60 GHz. The main emphasis was placed on a band-widening technique of the NRD guide beam-lead diode mount based on an electromagnetic field simulator, where each dimension of the beam lead diode mount was optimized. The agreement between the simulation and measurement is quite satisfactory. The up-converter fabricated by assembling a band-pass filter and a Schottky barrier diode mount has a good linearity as well as a flat output power of 2 dBm on the average over a bandwidth of at least 2 GHz. Moreover, the down-converter has a flat conversion loss performance of less than 7 dB in the same bandwidth. An NRD guide transmitter and a receiver characterized by small size and high performance were fabricated and successfully employed for the wireless distribution of TV signals for more than 100 channels.