Abstract: A release layer composed of AlGaAs, a strain layer, a strain compensation layer composed of an InGaAs, and a component layer are formed on a GaAs substrate. The component layer includes a DBR film. A recess for defining a bent region is formed in the component layer. The component layer, the strain compensation layer, the strain layer, and the release layer are removed in an approximately U shape, thereby forming a groove. The release layer under the strain layer is selectively removed. The strain layer is bent at a region below the recess so as to relax strain caused by the difference in the lattice constant between the InGaAs layer and the GaAs layer, and the component layer stands perpendicularly to the GaAs substrate.

Abstract: An array antenna apparatus includes a radiating element (6) for transmitting and receiving radio signals, and at least one parasitic element (7) arranged at a predetermined distance (d) away from the radiating element (6) and incapable of transmitting or receiving radio signals. The parasitic element (7) is connected with a variable-reactance element (23). A controller (100) changes the directivity of the array antenna by changing the reactance Xn of the variable-reactance element (23). The variable-reactance element (23) is a varactor diode (D, D1), for example, and the controller (100) changes the backward bias voltage Vb applied to the variable-reactance diode (D, D1) to change the capacitance of the varactor diode (D, D1), thus changing the directivity of the array antenna. The array antenna has a low-cost and simplified structure compared with the prior art, while facilitating directivity control.

Abstract: A communication network system includes a mobile node and a plurality of fixed nodes. The mobile node is a node moving along a predetermined route, and the fixed node is a node to be fixed along the predetermined route. A packet signal is sent to a destination node by way of those mobile nodes and fixed nodes. In other words, a packet communication among the fixed nodes is carried out by way of the mobile node.

Abstract: An array antenna apparatus for use in spread spectrum communications is provided including a plurality of antenna elements aligned on a straight line. The array antenna apparatus is used in a receiving station for receiving spread-spectrum modulated radio signals having a wavelength of a predetermined carrier frequency transmitted from transmitting stations using a two-dimensional RAKE receiving method, and for performing spread spectrum communications in code division multiple access. The plurality of antenna elements are aligned such that an interval between antenna elements adjacent to each other among the plurality of antenna elements is set to a value which is larger than one half the wavelength of the carrier frequency and which is equal to or smaller than sixteen times the wavelength of the carrier frequency so as to generate grating lobes.

Abstract: Disclosed is an optical control type phased array antenna apparatus having an array antenna of antenna elements. An optical signal processor optically processes input high-frequency signals, and outputs optically processed signals including signal components having phases corresponding to directions in which radio wave signals come and having frequencies equal to those of the input high-frequency signals. Then, each frequency converter mixes a received signal with the optically processed signal in correspondence with the antenna element, and outputs a frequency-converted signal having a frequency of a difference between a frequency of the received signal and a frequency of the optically processed signal. Further, a combiner combines the frequency-converted signals.