Schematic structure of RTD oscillators coupled with each other through a planar circuit.
Equivalent circuit of a coupled two-element oscillator.
Oscillation modes in a coupled two-element oscillator.
Condition of stability for coupled two-element oscillators.
Oscillation properties of coupled two-element oscillators as a function of difference between the individual frequencies of elements. (a) Normalized oscillation frequencies, (b) phase differences between elements, and (c) combined output power relative to single oscillator radiated to the direction normal to the antenna surface.
Measured oscillation spectra of a coupled two-element oscillator. Frequency differences between two RTDs are (a) 2 GHz and (b) 4 GHz, which are controlled by the bias voltage applied to one of the RTDs. Upper and lower curves in each diagram are individual and simultaneous oscillation of the two-elements, respectively.
Schematic structure of an -element oscillator array. (a) Plan view and (b) radiation of combined power within the plane containing the slot antennas and normal to substrate surface (-plane).
Approximate solutions of normalized amplitudes in array oscillators with (a) three and (b) five elements.
Combined output power of the fundamental mode in -element array relative to single oscillator radiated to the front direction [ in Fig. 7(b)]. Solid and dashed curves are results of exact and approximate calculations, respectively. Exact and approximate results are the same in .
Minimum value of the coupling parameter required for stable fundamental mode oscillation. Higher modes are unstable in the region where the fundamental mode is stable.
The influence of frequency distribution of array elements. (a) An example of frequency distribution used in the calculation, (b) combined output power of the fundamental mode relative to single oscillator radiated to the front direction [ in Fig. 7(b)] as a function of maximum frequency difference , and (c) radiation pattern of the combined output power for different values of .
Different array configurations and their combined output power. elements coupled (a) at the central pair and (b) at all the pair. (c) Combined output power relative to a single oscillator radiated to the front direction for the configurations in Fig. 7(a) (collinear ten elements), 12(a), and 12(b).
Article metrics loading...
Full text loading...