Axially symmetrical Fabry-Perot oscillator with multiple devices inserted in dielectric substrate

We investigate an axially symmetrical Fabry-Perot oscillator with active devices inserted in a dielectric substrate for power combining of many more devices in the microwave and millimeter wave frequency range. Empirically in this oscillator, efficient power combining can be done when it oscillates approximately at the frequency which corresponds to the wavelength equal to twice the spacing between the devices. The wavelength in the dielectric is shorter than in free space, so we tried to insert the devices in the dielectric substrate in order to increase the number of devices. By measuring the oscillation frequency of the oscillator with sixteen devices at X-band, we confirmed that the spacing between devices was about a half wavelength in the dielectric. We achieved almost perfect power combining of sixteen device

Hyper NRD guide oscillator with Gunn diodes mounted in the dielectric strip

Hyper NRD guide oscillators mounted with a single and multiple Gunn diodes have been investigated. The operating mode of the hyper NRD guide can be lower order by optimizing the structure of the guide. The Gunn diodes were arranged in the dielectric strip of the guide. In experiments at X-band, the oscillation frequencies could be varied by a movable shorting plane for the single diode case and an almost perfect power combining was obtained for the double diode cas

Axially symmetric Fabry-Perot power combiner with active devices mounted on both the mirrors

We investigate an axially symmetrical Fabry-Perot power combiner with many more active devices operating in axially symmetric TEM01n mode, which has an excellent feature of uniform device-field coupling required for high power combining efficiency. By numerical calculation using the boundary element method, it was shown that high combining efficiency can be obtained when a circular groove of larger radius is installed on either the plane mirror or the concave mirror. In experiments at X-band, almost perfect power combining of twenty or twenty-four Gunn diode oscillators mounted on both of the mirrors was achieve

Single and multiple Gunn diode oscillator using an image NRD guide

A single and a multiple Gunn diode oscillator using an image NRD guide have been investigated. The LSM01 mode which is the operating mode of the image NRD guide can be the dominant mode because undesired modes are suppressed due to existence of the image plane. In experiments at X-band for oscillators with Gunn diodes mounted in the dielectric strip of the image NRD guide, the oscillation frequencies could be varied by a movable shorting plane for the single diode case and an effective power combining operation was obtained for the double diode cas

Traveling-wave power divider with coplanar waveguide probes inserted into rectangular waveguide

A new traveling-wave power divider with coplanar waveguide probes is investigated. The divider is constructed by connecting successively the dividing units which consist of coplanar waveguide probe-pairs inserted into a rectangular waveguide and the thin narrow section. From experiments on fourand six-way dividers, wideband characteristics comparable to a divider with coaxial probes is demonstrate

Traveling-wave microwave power divider composed of reflectionless dividing units

We propose a new waveguide type traveling-wave microwave power divider that is adequate for high power applications. The divider is composed of multiple stages of reflectionless dividing units, each having two output ports. Design formulas for reflectionless equal-power dividing are first derived. Structural parameters for wideband design of two- to six-stage dividers are then obtained by means of numerical analyses based on an equivalent circuit. Comparison of experiments at X-band shows good qualitative agreement with the analyses. Typical measured bandwidth for relative divided powers deviation of less than ±0.5 dB was 2.7 GHz, and that for -20 dB return loss was more than 3.2 GHz for the four-stage (eight-way) divider. The divider presented here has excellent features; the bandwidth for equal-power dividing decreases very little and the bandwidth for low return loss increases with increasing number of the dividing stages. It also has advantages of low insertion loss and flexibility over the number of the dividing stage