The effect of AM noise on correlation phase noise measurements

We analyze the phase-noise measurement methods in which correlation and averaging is used to reject the background noise of the instrument. All the known methods make use of a mixer, used either as a saturated phase detector or as a linear synchronous detector. Unfortunately, AM noise is taken in through the power-to-dc-offset conversion mechanism that results from the mixer asymmetry. The measurement of some mixers indicates that the unwanted amplitude-to-voltage gain is of the order of 5-50 mV, which is 12-35 dB lower than the phase-to-voltage gain of the mixer. In addition, the trick of setting the mixer at a sweet point -- off the quadrature condition -- where the sensitivity to AM nulls, works only with microwave mixers. The HF-VHF mixers have not this sweet point. Moreover, we prove that if the AM noise comes from the oscillator under test, it can not be rejected by correlation. At least not with the schemes currently used. An example shows that at some critical frequencies the unwanted effect of AM noise is of the same order -- if not greater -- than the phase noise. Thus, experimental mistakes are around the corner.Comment: 16 pages, list of symbols, 8 figures, 27 reference

MIKSER MIKROFALOWY NA PROSTOKĄTNYCH FALOWODACH CZĘŚCIOWO WYPEŁNIONYCH DIELEKTRYKIEM

The article investigates and calculates the characteristics of microwave mixers on rectangular waveguides partially filled by dielectric. Presents diagrams of promising combined microwave radio engineering systems - two options for constructing mobile digital troposcatter-radiorelay stations, the antenna-feeder paths of which are implemented on rectangular waveguides partially filled by dielectric. At research of microwave mixers, suppression and the use of the mirror frequency are taken into account. The analysis of researches of microwave mixers is carried out. The design of a balanced-type microwave mixer based on rectangular waveguides partially filled by dielectric is developed. The mixer is used to convertion the microwave signal into an intermediate frequency signal. The signal conversion of the mixers takes place on the non-linear active resistance of the semiconductor diode. In article, an open nonlinear structure is used as such a diode. The following main parameters of microwave mixers are investigated: conversion losses, noise factor, operating frequency band, signal suppression at the mirror frequency. The conversion losses are determined for various mirror channel suppression conditions. Phase methods of mirror frequency suppression are considered, which are most suitable for the waveguide implementation of microwave mixers. A scheme of a microwave mixer of a balance type with a phase method for suppressing the mirror frequency is presented. The article notes that for significant suppression of the mirror frequency of more than 30 dB, a double frequency conversion mixer is used. A diagram of a slotted bridge based on rectangular waveguides partially filled by dielectric is presented. The dependences of the input impedance of the mixer, the impedance of the mixer at the intermediate frequency, the impedance of the mixer at the mirror frequency by the power of the local heterodyne are plotted.  W artykule zbadano i obliczono charakterystyki mieszaczy mikrofalowych na falowodach prostokątnych częściowo wypełnionych dielektrykiem. Przedstawiono schematy obiecujących połączonych mikrofalowych systemów inżynierii radiowej – dwóch opcji budowy mobilnych cyfrowych troposferycznych stacji radiowych, których tory antenowo-zasilające są realizowane na prostokątnych falowodach częściowo wypełnionych dielektrykiem. W badaniach mieszaczy mikrofalowych uwzględniono tłumienie i wykorzystanie częstotliwości lustrzanej. Przeprowadzono analizę badań mieszaczy mikrofalowych. Opracowano projekt mieszacza mikrofalowego typu zrównoważonego opartego na prostokątnych falowodach częściowo wypełnionych dielektrykiem. Mieszacz służy do konwersji sygnału mikrofalowego na sygnał o częstotliwości pośredniej. Konwersja sygnału mieszacza odbywa się na nieliniowej rezystancji czynnej diody półprzewodnikowej. W artykule jako taką diodę zastosowano otwartą strukturę nieliniową. Badane są następujące główne parametry mieszaczy mikrofalowych: straty konwersji, współczynnik szumów, pasmo częstotliwości roboczej, tłumienie sygnału na częstotliwości lustrzanej. Straty konwersji są określane dla różnych warunków tłumienia kanału lustrzanego. Rozważono fazowe metody tłumienia częstotliwości lustrzanej, które są najbardziej odpowiednie do falowodowej implementacji mieszaczy mikrofalowych. Przedstawiono schemat mieszacza mikrofalowego typu balansowego z fazową metodą tłumienia częstotliwości lustrzanej. W artykule zauważono, że w celu znacznego tłumienia częstotliwości lustrzanej o ponad 30 dB stosuje się mieszacz z podwójną konwersją częstotliwości. Przedstawiono schemat mostka szczelinowego opartego na prostokątnych falowodach częściowo wypełnionych dielektrykiem. Wykreślono zależności impedancji wejściowej mieszacza, impedancji mieszacza dla częstotliwości pośredniej, impedancji mieszacza dla częstotliwości lustrzanej od mocy lokalnej heterodyny

A GaAs MMIC chip-set for 10 to 15GHz radio-links applications

This paper describes the development of a GaAs MMIC chip-set for Ku-band radio-links transmitter. This chip-set includes two circuits, a times-two multiplier 5-7.5GHz to 10-15GHz, and a single side band up-converter. The development and the results of these circuits are analysed. The times-two multiplier is based on a specific balanced configuration leading to a very high level of input frequency suppression at the output (typically 50dBc) on a 2.7mm² chip. The mixer circuit is a broadband build-in single side band mixer of 10mm², with typically 30dBc image suppression

Application of CAD load_pull techniques in mixer design

This work describes the application of a commercial CAD software to implement load-pull techniques in the design of microwave mixers. This method is used to generate conversion-loss regions when a diode is pumped and operated as a mixer circuit. Emphasis is placed on the inclusion of image and out-of-band terminations to optimize the operating conditions required to obtain low conversion loss. An X-band 5-dB conversion-loss mixer is designed and tested using this method.Peer Reviewe

The Design and Implementation of an Interdigitated Directional Coupler for Use in Microwave Mixers

The purpose of this thesis is to present a design for a balanced microwave mixer, operating in the X-band region(S-12 GHZ). The major emphasis of this work is on the coupling structure of the mixer. A 3-db interdigitated Lange coupler is designed, fabricated, and tested. The design obtained through numerical procedures is compared with that obtained with the TOUCHSTONE CAD package. A brief comparison between this coupler and other commonly used couplers is also presented. The diode circuitry of the mixer is discussed in detail, focusing mainly on the operation of the Schottky barrier diode, and finally a total layout of the mixer is discussed

Application of CAD load-pull techniques in mixer design

This work describes the application of a commercial CAD software to implement load-pull techniques in the design of microwave mixers. This method is used to generate conversion-loss regions when a diode is pumped and operated as a mixer circuit. Emphasis is placed on the inclusion of image and out-of-band terminations to optimize the operating conditions required to obtain low conversion loss. An X-band 5-dB conversion-loss mixer is designed and tested using this methodPostprint (published version

A 530-GHz balanced mixer

We report on the design and performance of a 530-GHz balanced SIS mixer, the first balanced mixer in this frequency range. This quasi-optical balanced mixer utilizes a cross-slot antenna on a hyperhemispherical substrate lens with eight superconductor-insulator-superconductor (SIS) junctions and a 180° lumped element IF hybrid circuit. The local oscillator (LO) and the radio frequency (RF) signal, orthogonal in polarization to each other, are coupled to the mixer using a wire-grid polarizer. The noise performance of the mixer is excellent, giving an uncorrected receiver noise temperature of 105 K (DSB) at 528 GHz

Theoretical and experimental assessment of the non-linear scattering functions for the cad of non-linear microwave circuits

The Non-Linear Scattering Functions have been theoretically defined and experimentally measured for the linear-equivalent design of non-linear circuits in arbitrary large signal conditions. Non-linear measures and simulations have been compared, with good agreement. Linear CAD concepts can therefore be extended to non-linear circuits in a rigorous way