CN2562496Y - Phase shifter of miniature radio-frequency mechanism system - Google Patents

Abstract

The utility model relates to a method for realizing phase displacement using high pass/low pass filter network of RF MEMS switch. Two groups of RF MEMS switches are connected in each displaced phase signal input/output circuit, and each group is composed of two RF MEMS switches; and the two groups of the switches are respectively connected in a low pass filter network branch and a high pass filter network branch. The utility model has the advantages of small volume, high phase displacement accuracy, and high reliability.

Description

The radio frequency micro-mechanic system phase shifter

Technical field

The utility model is the phase shifter about Phased Array Radar Antenna wave beam control usefulness, specifically a kind of radio frequency micro-mechanic system phase shifter.

Technical background

The phase shifter of control Phased Array Radar Antenna wave beam, traditional way is to adopt PIN diode and field-effect transistor (FET) configuration to make, but because PIN diode or the intrinsic shortcoming of FET, make its phase shifter performance also have shortcoming, as: because the unsteadiness of Semiconductor substrate metal contact layer and semiconductor junction causes the RF loss bigger; Because causing, semiconductor junction and parasitic capacitance etc. produce nonlinear distortion RF number; Because what use is that active device makes that integrated circuit tangerine structure power consumption is big, volume is big; Because complex structure, difficulty of processing cause rate of finished products low greatly, manufacturing cost height or the like.Adopt novel radio frequency micro-mechanic system (RFMEMS) phase shifter to carry out the control of phased array radar wave beam and can overcome above-mentioned some shortcomings, but (referring to documents: what Low-Loss Cascadable MEMS Distributed X-BandPhase Shifters) its structure adopted is co-planar waveguide (CPW) load line style to existing RFMEMS phase shifter, the mechanism of phase shift is based on the even CPW transmission line and loads with a little reactance, promptly change normalized susceptance and change phase shift, its shortcoming is that the capacitance variations when ON state and OFF state of each RF mems switch compares less, the reactance that changes phase shift is very little, need the cascade of many RF mems switches could realize certain phase shift, need the cascade of more than 20 RF mems switch as one 3 RF MEMS phase shifters, this just makes the integrated circuit structural volume increase, the phase shift precision is not high, reliability decrease.

Summary of the invention

The purpose of this utility model provides that a kind of integrated circuit structure is less, the phase shift precision is higher, reliability RF MEMS phase shifter preferably.

The utility model technical solution:

The utility model adopts RF mems switch high pass-low-pass filter network to realize phase shift, promptly in each phase shift signal imput output circuit, inserts two groups of RF mems switches, is made up of two RF mems switches again for every group; Two groups of switches are connected in low pass and the high-pass filtering branch of a network.

Advantage of the present utility model:

RF MEMS phase shifter has compared with the phase shifter that traditional PIN diode or FET make that to insert loss little, low in energy consumption, do not have conventional harmonic distortion, and a low cost and other advantages, to have compared volume little with external existing RF MEMS phase shifter design, phase shift precision height, advantages such as high reliability.

Description of drawings

Fig. 1 is RF MEMS phase shifter high pass-low-pass filter network circuit theory diagrams.

Embodiment

Below in conjunction with accompanying drawing the utility model is further described:

The utility model is made up of low-pass filter network branch road 1 and high-pass filtering branch of a network 2, and wherein branch road 1 comprises RF MEMS K ₁, inductance L ₁, inductance L ₂, RF MEMS K ₂, capacitor C ₁, inductance L ₁, inductance L ₂With RF MEMS K ₁, MEMS K ₂Be connected on the branch road 1 capacitor C ₁Be connected in parallel on inductance L ₁, inductance L ₂Between, and ground connection.Branch road 2 comprises RF MEMS K ₃, capacitor C ₂, RF MEMS K ₄, inductance L ₃, inductance L ₄, capacitor C ₂With RF MEMS K ₃, RF MEMS K ₄Be connected on the branch road 2 inductance L ₃, inductance L ₄Be connected in parallel on capacitor C respectively ₂Both sides, and ground connection.Under the effect of biasing control voltage, two RFMEMS switches alternately " are opened " or " pass ", and make the RF signal code alternately by low-pass filter network branch road and high-pass filtering branch of a network, at this moment, the former produces a leading phase place, the latter produces a phase place that falls behind, and what produce between the two condition differs the numerical value decision of Δ φ by inductance in the filter network or electric capacity: $\mathrm{\Δ\φ}={2\tan }^{-1}\{-\frac{\mathrm{Bn}+2\mathrm{Xn}-\mathrm{Bn}{\mathrm{Xn}}^2}{2(1-\mathrm{BnXn})}\}$

Bn: admittance Xn: impedance

As long as determine and regulate the numerical value of Bn and Xn, can realize certain phase shift, thereby realize the phase shift of multidigit high accuracy.This structure has more advantage to the phase shift of high phase place.Only need 4 RF mems switches owing to realize every phase shift again, and make the load line structure into high pass-low-pass filter network structure, can reach the purpose that volume is less, reliability is higher.

Claims (3)

1. a radio frequency micro-mechanic system phase shifter is characterized in that inserting two groups of RF mems switches in each phase shift signal imput output circuit, is made up of two RF mems switches again for every group; Two groups of switches are connected in low pass and the high-pass filtering branch of a network.

2. radio frequency micro-mechanic system phase shifter according to claim 1 is characterized in that inductance L ₁, inductance L ₂With RF MEMS K ₁, RF MEMS K ₂Be connected on the low-pass filter network branch road 1 capacitor C ₁Be connected in parallel on inductance L ₁, inductance L ₂Between, and ground connection.

3. radio frequency micro-mechanic system phase shifter according to claim 1 is characterized in that capacitor C ₂With RF MEMS K ₃, RF MEMS K ₄Be connected on the high-pass filtering branch of a network 2 inductance L ₃, inductance L ₄Be connected in parallel on capacitor C respectively ₂Both sides, and ground connection.