Abstract: A radar system is described, which includes a built-in calibration/fault detection apparatus that enables rapid and easy calibration of the system. The system includes a long extrusion (70) forming a feed waveguide (90), a calibration waveguide (92), and a base (94) of a horn antenna. A linear array of TR (transmit/receive) units (42) are mounted on the extrusion, with each having a feed probe (100) that receives a feed signal, changes its phase and amplifies it, and delivers it through a monopole (110) to the horn. The calibration waveguide is coupled through holes (130) to the horn, with a calibration pickup (132) mounted at the end of the calibration waveguide. During calibration, one TR unit at a time is energized, and its output is detected by the calibration pickup to check the amplitude and phase of the TR unit.

Abstract: A high gain antenna that produces a pencil beam along the ground and a lower gain antenna that produces a beam extending above the pencil beam are coupled to a source of r.f. pulses so that the amplitude of the r.f. pulses applied to the high gain antenna is less than the amplitude of the r.f. pulses applied to the lower gain antenna during airplane detection and the full amplitude of the r.f. pulses during a pulse segment is applied to the high gain antenna during wind pattern detection.

Abstract: A modified branch line coupler amplitude equalizer circuit employing cross arms and branch lines of varying lengths and impedances to minimize the return loss of the circuit.

Abstract: A two port dual bandpass microwave filter consisting of "n" resonant cavities. Each cavity resonates in two independent modes at displaced frequencies so that the filter has two passbands in a desired frequency band. By orienting an incoming waveguide at an angle with respect to the filter, both TE and TM modes can be excited to produce two separate passbands. The passbands may have either equal or unequal characteristics. Fine tuning of the TE and TM modes is accomplished using tuning plungers or tuning screws. The dual bandpass response of the new filter is achieved by utilizing the TE.sub.1,1,1 and TM.sub.0,1,0 modes in right circular cylindrical cavities, or equivalent modes in rectangular, or other cavities. These modes are orthogonal so they do not couple to each other. The cavity loaded Qs are independently adjustable, so the two passbands can have the same or different bandwidths, the same or different amplitude ripples and the same or different phase responses.

Abstract: The present invention constitutes a microwave circuit structure such as a phase shifter which has a dielectric cylindrical support structure with a ground plane on the inside and a microwave circuit mounted on the outside. A cylindrical shield is mounted coaxially around the circuit, spaced therefrom by a second dielectric.Two embodiments are shown in microstrip and stripline.

Abstract: The variable directional coupler of the subject invention employs 3, 4 or n branches in TEM transmission media, such as coax, stripline and microstrip. Precise control of the coupling is acheived by a variable susceptance connected near the mid-point of the crossover.

Abstract: An antenna feed network implemented preferably in stripline for connecting the elements of a linear or planar array with a common port for transmit/receive operation. The network acts as a power divider/combiner and is entirely reciprocal. The network is realized in the form of a pattern of conductive traces on a single dielectric sheet of the stripline arrangement between parallel, spaced ground planes and does not require interconnections among multiple planes. The network may be utilized as a single or multiple beam forming network with the path lengths to the respective array radiators patterned to achieve a frequency scanning or beam normal array design.

Abstract: An improved serpentine feed and method of making same. The invention includes a block of conductive material having a primary microwave waveguide channel and at least one secondary channel. Each secondary channel has at least one broadwall common to the primary channel. A high performance coupler is provided in the common broadwall by which microwave energy communicates from the primary channel to the secondary channel.

Abstract: An antenna element including a microstrip radiating element having a microstrip feed line and a ground plane on opposite sides of a substrate, with at least one of a plurality as resonators on the same side of the substrate as the microstrip feed line, and a dipole radiator having an increased bandwidth and insulated from the feed line and from the plurality of resonators.

Abstract: This invention relates to two embodiments of microwave polarization control networks. The first produces two sets of orthogonal linear polarizations and constitutes a two position transfer switch and a directional coupler having two ports alternating as input and isolated ports and two ports alternating as through and coupled output ports. The transfer switch is connected to switch an input to one or the other of the two ports alternating as input and isolated ports and couple the other to a termination. An ortho-mode transducer junction, having two input ports, has one input port coupled directly to one of the output ports of the directional coupler and the other input port connected in series through a 0.degree./180.degree. phase shifter to the other output port of the directional coupler. A dual mode waveguide is employed for transmitting a variable polarization output from the ortho-mode junction. In another embodiment, the transfer switch is not employed, and a 90.degree.

Abstract: An antenna element including microstrip having a microstrip feed line and ground plane on opposite sides of a substrate, a resonator on the same side of the substrate as the microstrip feed line, and a dipole insulated from the feed line and from the resonator.

Abstract: A broadband TEM mode four-port hybrid in a single-level microwave circuit in a transmission line medium selected from among the stripline, microstrip, airstrip, etc. media. The device employs coupled strip all-pass filter elements to provide a hybrid wherein isolation to the cross ports, power division to the coupled ports, and the 0.degree. and 180.degree. output phase relationships are independent of frequency over substantial frequency bandwidths.

Abstract: A TEM mode balun in a single-level microwave circuit in a transmission line medium selected from among the stripline, microstrip, airstrip, etc. media. The device employs coupled-strip all-pass filter elements to provide a pair of balanced input/output lines in 180.degree. phase relationship and an unbalanced line port.