Bidirectional antennas

Fig. 1 shows the block diagram of the vibrometer, in which the most sensible to small phase variations interferometric scheme is employed. It consists of the microwave and the display units. The display unit consists of the power supply 1, controller 2 of the phase modulator 3, microprocessor unit 9 and low-frequency amplifier 10. The microwave unit contains the electromechanical phase modulator 3, a solid-state microwave oscillator 4, an attenuator 5, a bidirectional coupler 6, a horn antenna 7 and a microwave detector 11. The horn antenna is used for transmitting the microwave and receiving the reflected signal, which is mixed with the reference signal in the bidirectional coupler. In the reference channel the electromechanical phase modulator is used to provide automatic calibration of the instrument. To adjust the antenna beam to the object under test, the microwave unit is placed on the platform which can be shifted in vertical and horizontal planes. 

Figure 7 Simplified view of a bidirectional photonic antenna. The middle part shown in tight gray contains donor molecules D. After excitation of D to D, the excitation energy migrates with equal probability to the left and to the right until it reaches an acceptor A (dark gray) which captures the excitation energy and emits it as red-shifted light.

Figure 2.5 Principle setup of two-dimensional, constructal network (a) Unidirectional network with fork-like structure and four levels (b) bidirectional network with antenna-like structure and six levels.

---