Small Antennas: Miniaturization Techniques and Applications

Abstract

Original scientific paperThe paper presents research results in the field of small antennas obtained at the Department of Wireless Communications, Faculty of Electrical Engineering and Computing, University of Zagreb. A study comparing the application of several miniaturization techniques on a shorted patch antenna is presented. Single and dual band shorted patch antennas with notches and/or slot are introduced. A PIFA designed for application in mobile GSM terminals is described. The application of stacked shorted patches as array elements for a mobile communication base station as well as for electromagnetic field sensor is presented. The design of single and dual band folded monopoles is described. Prototypes of the presented antennas have been manufactured and their characteristics were verified by measurements. Male antene: postupci smanjivanja izmjera i primjene. U radu su prikazani rezultati istraživanja u području malih antena ostvareni na Zavodu za Radiokomunikacije, Sveučilišta u Zagrebu Fakulteta elektrotehnike i raču-narstva. Prikazana je primjena više postupaka za smanjivanje izmjera skraćene mikrotrakaste antene. Opisane su izvedbe skraćenih mikrotrakastih antena s urezima i prorezom za rad u jednom i u dva frekvencijska područja. Prikazana je izvedba planarne invertirane F-antene (PIFA) za primjenu u ručnim terminalima sustava pokretnih komunikacija GSM. Višeslojne skraćene mikrotrakaste antene uporabljene su za izvedbu antenskog niza za baznu postaju sustava pokretnih komunikacija te kao elementi osjetila za mjerenje jakosti elektromagnetskog polja. Prikazana je izvedba savijenih monopolnih antena za rad u jednom te u dva frekvencijska pojasa. Izraîeni su prototipovi opisanih antena i mjerenjima su ispitane njihove osobine.Ključne riječi: mala antena, planarna antena, skraćena mikrotrakasta antena, PIFA, višeslojna mikrotrakasta antena, savijeni monopol, dvofrekvencijska antena

Compact triple‐band PIFA with high bandwidth and gain for multiple mobile services

“…The PIFA380LDE, microstrip antenna has two compact short circuits connected to the ground plane . The short introduces a return path for the surface currents of the antenna and triggers resonance for electrical dimensions smaller than half‐a‐wavelength .…”

“…Several techniques and approaches have been introduced to reduce antenna dimensions and maintain good radiation properties . Research and development of small antennas is of great importance for all future wireless applications . Patch antennas offer several advantages over classical antennas like low cost, easy fabrication, planar shape, conformability, etc .…”

“…Patch antennas offer several advantages over classical antennas like low cost, easy fabrication, planar shape, conformability, etc. . The details of the manufacturing procedures of the prototype antenna and experimental results are studied and discussed in this article.…”

A novel rectifying circuit for microwave power harvesting system

“…Cockcroft‐Walton is a voltage multiplier developed by Greinacher that was enhanced by Walton and Cockcroft with an intent to develop high‐energy positive ion beams . This generator is an electric circuit consisting of a cascading network of capacitors and diodes to generate high voltage (DC) from a pulsating DC input or a low AC voltage.…”

Miniaturised antenna at a sub‐GHZ band for industrial remote controllers

“…In the literature, most of the miniaturisation studies have been conducted for frequencies of upper GHz bands or multi-band operations [4][5][6][7][8][9]. Various techniques have already been proposed such as the use of highdielectric substrate, multilayer structures [10,11], introducing slots and notches [12], fractal shaped patches [4,13], various shape strips and loop structures [5,[14][15][16][17], and employing metamaterial loading techniques [7,18]. Using high-dielectric substrate material, so-called superstrate, increases the quality factor but it also causes an increase in electric field concentration [19].…”