IRE Transactions on Microwave Theory and Techniques

Possibilities of a small-bandwidth, small-insertion loss, magnetically tunable band-pass filters with nonreciprocal characteristics have been studied. the unloaded Q(Qu) for a ferrimagnetic sample has been derived, considering the fundamental definition of Q for a resonator. Theoretical analysis is given for coupling due to ferrimagnetic resonance, between two RF transmission circuits w... View full abstract»

The velocity of surface-wave propagation on two types of axially modulated corrugated rods has been measured experimentally. Type A has a constant outer diameter and sinusoidally varying slot depth, while in type B the slot depth varies in virtue of a modulated outer diameter. In both cases the measured phase velocity is about ten per cent less than that for a uniformly corrugated rod with the ave... View full abstract»

A general formulation for the back-scattered field from loaded objects is given. It is shown that small resonant objects produce a much greater back-scattered field than small nonresonant ones. The theory is applied to short dipoles and small loops. The use of small resonant scatterers to measure electric and magnetic fields by scattering techniques is discussed. Resonant scatterers are found to h... View full abstract»

A new procedure of matching is presented, based in the equations which transform the output reflection coefficient of a lossless two-port network into the input reflection coefficient. The parameters of the equations are the residual reflection coefficients which can be easily measured. The optimum reflection coefficients which have the minimum frequency variation are computed for the specific cas... View full abstract»

An X-band electrically-tunable ferroelectric phase shifter has been constructed. The phase shifter is reciprocal and consists of a thin ferroelectric slab completely filling the transverse plane of a rectangular waveguide with suitable dielectric matching sections placed symmetrically about the slab forming a band-pass filter. Phase shift is controlled by applying a dc electric field to the ferroe... View full abstract»

A balanced-type diode amplifier is reported, in which the cutoff mode of the pumping waveguide resonating with the diode capacitances, is used as a signal circuit and a series connected diode loop is used as an idler. Theoretical noise-figure and gain-bandwidth product are derived after calculating the equivalent susceptance of two diodes which are parallel-connected for the signal input and serie... View full abstract»

The paper gives a survey of the literature concerning the electromagnetic properties of wire grids. As an introduction to the literature survey, a short description of the properties and applications of wire grids is given. Finally some particular grid configurations are mentioned. View full abstract»

The conditions for TE mode propagation in rectangular waveguides with nonuniform dielectric media are established. An equation is derived for determining the capacitivity functions which have equivalent curved waveguides with uniform dielectric media. The types of variable dielectric waveguides which have equivalent curved wall waveguides and a separable wave equation are determined. View full abstract»

A method of stabilizing receivers for radio telescopes is discussed and shown to be capable of substantially reducing sensitivity to gain fluctuations. The system employs a variable noise source as a controlled feedback element. Such a system does not require long warm up times since the output is dependent only upon the stability of the variable noise source and reaches stabilization very rapidly... View full abstract»

The use of an electric probe for measurement of induced surface currents on obstacles in a parallel plate region is described. An analysis of the sources of error, and in particular the interaction of the probe with the obstacle, is examined theoretically and experimentally. It is concluded that the technique is capable of yielding measurements of good accuracy. View full abstract»

In this note, experimental results will be presented for practical coaxial and waveguide band-pass filters. Filters of both types were originally developed in the 1700 Mc to 2300 Mc frequency range for application in a wide-band microwave radio relay communications system. The specifications for these filters called for very low input VSWR's over an appreciable part of the filter pass bands. This ... View full abstract»

Through the use of the familiar hybrid directional coupler and two PIN junction diodes as load impedances, the power delivered to the port not directly coupled to the input may be limited to any desired level, without rigid tolerances on the diode impedances. Starting with the scattering matrix of the hybrid and specifying arbitrary load reflection coefficients, the general properties of the devic... View full abstract»

Numerous ways are known for resolving a polarized microwave signal into pairs of orthogonally polarized components. Although pairs of orthogonal components contain redundant information, in many experimental applications it is desirable to have both linearly polarized and circularly polarized components available for comparison purposes. These four polarization components are derived simultaneousl... View full abstract»

A waveguide propagating the TE10 mode can carry more power than the normal rectangular waveguide if it has a symmetrically placed channel in the E-plane as shown in fig. 1. The greater height of the channel in the center of the waveguide will allow a higher voltage to be applied before dielectric breakdown occurs. The TE10 cutoff wavelength λc was investigat... View full abstract»

A relatively simple form of microwave frequency diplexer consists of a waveguide E- or H-plane Y-junction terminated with baudpass filters in each of the two output ports. The E- or H-plane bifurcation, or zero-degree Y-junction, allows a compact diplexer design as shown in Fig. 1. View full abstract»