A printed leaky‐wave antenna with stable gain and reduced cross‐polarization level is presented in this letter. The proposed antenna has the property of continuous backward‐to‐forward beam scanning with symmetrical scanning. The proposed antenna's unit cell consists of two unequal inclined stubs connected to a microstrip line. The angle between the stubs and their dimensions is designed optimally to obtain improved antenna performance. The antenna provides stable gain with peak gain 14.4 dBi and gain variation 2.55 dBi in the operating band 9.5–15 GHz. The maximum value of cross‐polarization level along the main beam is −30 dB. The design gives a scanning angle of 73° from −36° to +37° through broadside. Another important feature of the proposed antenna is that there is no gain reduction at the broadside radiation.

Printed leaky‐wave antenna with stable gain and reduced cross polarization

Symmetric periodic leaky-wave antenna for open stopband suppression

In this work, a new microstrip circularly polarized leaky-wave antenna is presented for X -band applications. The design of the proposed leaky-wave antenna is inspired by the conventional 3 dB branch-line coupler. The geometry of the unit cell of the proposed leaky-wave antenna is realized by removing the two collinear feed lines of the branchline coupler. The open stopband is eliminated by optimizing the geometry. The proposed leaky-wave antenna provides impedance bandwidth with | S11 | < -10 dB between 8.2-11.1 GHz. The bandwidth corresponding to axial ratio < 3 dB is 9.4-10.3 GHz. The antenna radiates in the broadside at 9.9 GHz with 14.1 dBic gain.

Branch Line Coupler Inspired Circularly Polarized Leaky-Wave Antenna with Broadside Scanning

In this letter, a novel circularly polarized microstrip leaky-wave antenna is proposed with broadside radiation and high gain. A conventional microstrip patch has been modified to obtain broadside gain along with circular polarization. The modified patch is periodically placed along one side of the 50 Ω delay line to form leaky-wave antenna. The optimized broadside frequency of the antenna is 10.1 GHz. The bandwidth associated with 3-dB axial ratio is 13.3% while the maximum obtained gain is 15.8 dBic. The measured gain variation within 3-dB axial ratio bandwidth is 1.6 dB. Measured results of the fabricated antenna follow the simulations. 

Microstrip Leaky-Wave Antenna with Circular Polarization and Broadside Radiation

In this work, a novel periodic leaky-wave antenna (P-LWA) based on slot-loaded half mode substrate integrated waveguide (HMSIW) is proposed. The P-LWA unit cell contains two identical open-ended stubs spaced close to quarter wavelength apart to suppress the open stopband (OSB). The proposed leaky-wave antenna provides impedance bandwidth with $S$11< −10 dB between 10.3-15.1 GHz. The antenna radiates in the broadside at 12.5 GHz with 14.7 dBi gain and has a peak gain of 17.2 dBi at 14.9 GHz.

Open Stopband Suppressed Half-Mode Substrate Integrated Waveguide Based Leaky-Wave Antenna for Forward and Backward Beam Scanning

In this work, a comb-line leaky-wave antenna with a pair of wide stubs is proposed with enhanced gain and reduced cross-polarization. To ensure broadside scanning, three sections of transmission lines are used in the stub with the longitudinal offset. The stubs are placed half-wavelength apart on both sides of the delay line to achieve high gain and a low-cross polarization level. The antenna provides 46.8% impedance bandwidth with |S11| below −10 dB. The maximum measured gain and total efficiency are 18.5 dBi and 85%, respectively. The optimized broadside frequency of the leaky-wave antenna is 10.2 GHz. 

Ayaz Ahmad

Papers

Symmetric periodic leaky-wave antenna for open stopband suppression

Branch Line Coupler Inspired Circularly Polarized Leaky-Wave Antenna with Broadside Scanning

Microstrip Leaky-Wave Antenna with Circular Polarization and Broadside Radiation

Open Stopband Suppressed Half-Mode Substrate Integrated Waveguide Based Leaky-Wave Antenna for Forward and Backward Beam Scanning

Broadside scanning comb‐line leaky‐wave antenna with gain enhancement and reduced cross‐polarization