ECRI Microelectronics

Radio frequency channel miniaturization products

Radio frequency channel miniaturization products
The miniaturization technology of microwave hybrid integrated circuit in thin film division focuses on local circuit design, modularization, miniaturization, structural packaging, improvement of consistency and reliability. The original rf channel products are miniaturized by the thin-film technology, that is, some circuits in the rf channel are processed with higher precision and better reliability by the thin-film technology, which is encapsulated in the shielding metal air-tight enclosure with good heat dissipation by the high-density assembly method.

The following is an example of an l-band radio frequency channel and its miniaturization technology. This type of product index is closely related to antenna index, data processing and other system requirements, and mainly develops in cooperation with users.

2.1 Technical characteristic
Rf channel schematic diagram
radio-frequency-channel-miniaturization-products
RF antenna array is divided into GNSS channel and XXX channel. The GNSS channel is a single channel designed with existing mature circuits. The RF channel of XXX is mainly composed of filter, low-noise amplifier, up-down converter, amplifier, clock module, frequency source and DC_DC power supply.

Radio frequency (RF) channel to channel phase consistency, consistency, isolation, gain phase stability have higher requirements, so the miniaturization of the thin film hybrid integrated process on how to send and receive passage, each channel by encapsulation structure consistent separation chamber, the channel module respectively complete RF signal amplification and frequency conversion, and other functions, in order to achieve the high demand.
Table 9 Radio frequency channel electrical characteristics

characteristics

symbol

Conditions

RF input frequency:xxxx.5MHz±10MHz;

RF input power:-130dBm~-40dBm

LO input frequency:xxxx MHz;

LO input power:0dBm

Limit value

Unit

Min

Max

Channel gain

G


45

55

dB

Gain consistency

ΔG


-

2

dB

Image rejection

S1


65

-

dBc

Harmonic suppression

H1


65

-

dBc

Working current

I


0.35

0.4

A

Noise Figure

NF



2.5


RF port standing wave ratio

VSWR


-

2

-

Phase consistency

ΔPh

TA=25℃

-5

5



2.2 Radio frequency channel miniaturization technology


  • Selection of components
Raw chip or micro-label encapsulated components are selected for hybrid integration to improve the integration degree and effectively reduce the circuit area.
  • Thin film substrate manufacturing
The environmental requirements for radio frequency channels are relatively high, and the base plate is required to ensure the dielectric constant while having higher thermal conductivity. The material selection and manufacturing are studied to meet the practical requirements.

(1)Substrate selection
Aluminum oxide (AL2O3) is usually selected for the substrate, which has the advantages of large dielectric constant, small dielectric loss, large insulation resistance, high mechanical strength, and close to the coefficient of thermal expansion of the package shell. Aluminum nitride (ALN) is preferred on the base plate of power device, with the dielectric constant of 8.7 and thermal conductivity of 200W/m•K. Ceramic substrates have many excellent properties, and they play a more important role than PCB in the field of microwave communication. With high dielectric constant of thin film substrate, can shrink the same electrical length microwave signal in the medium plate length and width of resistance attenuation network also can be directly generated on thin film substrate, thus greatly reducing the area of the original circuit, and improved the precision of attenuation at the same time, the existing module in, consistency, reliability, maintainability, scalability, etc, have certain ascend.

(2)Selection of conductive metal materials
Parts of the RF channel need to be assembled by welding process. The metal on the substrate is required to have good weld ability, weld ability and resistance and large current, so as to guarantee welding strength and reliability. In addition, the radio frequency circuit has requirements on the band impedance and skin depth of the radio frequency signal, so it adopts the method of gilding the micro strip line to meet the requirements of the radio frequency signal.

(3)Wire and through hole design
The key to high performance and repeatability in microwave structures is determined by the geometry of the metal and the characteristic impedance of the transmission line is determined by the width of the line. The whole RF channel has small volume, high wiring density and small wire width, so the precision requirements are very high. Metalized through-holes are commonly used to connect radio frequency signals to encapsulated areas, requiring better mechanical strength and lower electrical impedance.

  • Micro assembly technique


The single-channel module adopts welding technology to weld the substrate inside the cavity to ensure good grounding. The input and output interfaces, such as RF, TLO, RLO, IF, +VCC and -vcc, are respectively connected with the antenna and the system-level substrate.

Aimed at circuit performance and reliability, the interconnect process parameters such as high consistency and high reliability bonding of rf channel circuits are controlled. By using the electromagnetic model, the parameters are converted into an equivalent circuit, which is involved in the simulation analysis of the whole circuit and guides the design and test.
Radio frequency channel miniaturization products
Model Series Max. Output Power (W) Input DC Voltage (V) Output Voltage (V)